powerpc/io: Add __raw_writeq_be() __raw_rm_writeq_be()

Add byte-swapping versions of __raw_writeq() and __raw_rm_writeq().

This allows us to avoid sparse warnings caused by passing __be64 to
__raw_writeq(), which takes unsigned long:

  arch/powerpc/platforms/powernv/pci-ioda.c:1981:38:
  warning: incorrect type in argument 1 (different base types)
      expected unsigned long [unsigned] v
      got restricted __be64 [usertype] <noident>

It's also generally preferable to use a byte-swapping accessor rather
than doing it by hand in the code, which is more bug prone.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>

arch/powerpc/include/asm/io.h

@@ -367,6 +367,11 @@ static inline void __raw_writeq(unsigned long v, volatile void __iomem *addr)
 	*(volatile unsigned long __force *)PCI_FIX_ADDR(addr) = v;
 }
 
+static inline void __raw_writeq_be(unsigned long v, volatile void __iomem *addr)
+{
+	__raw_writeq((__force unsigned long)cpu_to_be64(v), addr);
+}
+
 /*
  * Real mode versions of the above. Those instructions are only supposed
  * to be used in hypervisor real mode as per the architecture spec.
@@ -395,6 +400,11 @@ static inline void __raw_rm_writeq(u64 val, volatile void __iomem *paddr)
 		: : "r" (val), "r" (paddr) : "memory");
 }
 
+static inline void __raw_rm_writeq_be(u64 val, volatile void __iomem *paddr)
+{
+	__raw_rm_writeq((__force u64)cpu_to_be64(val), paddr);
+}
+
 static inline u8 __raw_rm_readb(volatile void __iomem *paddr)
 {
 	u8 ret;