LoongArch: Add __percpu annotation for __percpu_read()/__percpu_write()

When build kernel with C=1, we get:

arch/loongarch/kernel/process.c:234:46: warning: incorrect type in argument 1 (different address spaces)
arch/loongarch/kernel/process.c:234:46:    expected void *ptr
arch/loongarch/kernel/process.c:234:46:    got unsigned long [noderef] __percpu *
arch/loongarch/kernel/process.c:234:46: warning: incorrect type in argument 1 (different address spaces)
arch/loongarch/kernel/process.c:234:46:    expected void *ptr
arch/loongarch/kernel/process.c:234:46:    got unsigned long [noderef] __percpu *
arch/loongarch/kernel/process.c:234:46: warning: incorrect type in argument 1 (different address spaces)
arch/loongarch/kernel/process.c:234:46:    expected void *ptr
arch/loongarch/kernel/process.c:234:46:    got unsigned long [noderef] __percpu *
arch/loongarch/kernel/process.c:234:46: warning: incorrect type in argument 1 (different address spaces)
arch/loongarch/kernel/process.c:234:46:    expected void *ptr
arch/loongarch/kernel/process.c:234:46:    got unsigned long [noderef] __percpu *

Add __percpu annotation for __percpu_read()/__percpu_write() can avoid
such warnings. __percpu_xchg() and other functions don't need annotation
because their wrapper, i.e. _pcp_protect(), already suppresses warnings.

Also adjust the indentations in this file.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311080409.LlOfTR3m-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311080840.Vc2kXhfp-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311081340.3k72KKdg-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311120926.cjYHyoYw-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311152142.g6UyNx1R-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311160339.DbhaH8LX-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311181454.CTPrSYmQ-lkp@intel.com/Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/percpu.h

@@ -40,13 +40,13 @@ static __always_inline unsigned long __percpu_##op(void *ptr,		\
 	switch (size) {							\
 	case 4:								\
 		__asm__ __volatile__(					\
-		"am"#asm_op".w"	" %[ret], %[val], %[ptr]	\n"		\
+		"am"#asm_op".w"	" %[ret], %[val], %[ptr]	\n"	\
 		: [ret] "=&r" (ret), [ptr] "+ZB"(*(u32 *)ptr)		\
 		: [val] "r" (val));					\
 		break;							\
 	case 8:								\
 		__asm__ __volatile__(					\
-		"am"#asm_op".d" " %[ret], %[val], %[ptr]	\n"		\
+		"am"#asm_op".d" " %[ret], %[val], %[ptr]	\n"	\
 		: [ret] "=&r" (ret), [ptr] "+ZB"(*(u64 *)ptr)		\
 		: [val] "r" (val));					\
 		break;							\
@@ -63,7 +63,7 @@ PERCPU_OP(and, and, &)
 PERCPU_OP(or, or, |)
 #undef PERCPU_OP
 
-static __always_inline unsigned long __percpu_read(void *ptr, int size)
+static __always_inline unsigned long __percpu_read(void __percpu *ptr, int size)
 {
 	unsigned long ret;
 
@@ -100,7 +100,7 @@ static __always_inline unsigned long __percpu_read(void *ptr, int size)
 	return ret;
 }
 
-static __always_inline void __percpu_write(void *ptr, unsigned long val, int size)
+static __always_inline void __percpu_write(void __percpu *ptr, unsigned long val, int size)
 {
 	switch (size) {
 	case 1:
@@ -132,8 +132,7 @@ static __always_inline void __percpu_write(void *ptr, unsigned long val, int siz
 	}
 }
 
-static __always_inline unsigned long __percpu_xchg(void *ptr, unsigned long val,
-						   int size)
+static __always_inline unsigned long __percpu_xchg(void *ptr, unsigned long val, int size)
 {
 	switch (size) {
 	case 1: