LoongArch: Disable module from accessing external data directly

The distance between vmlinux and the module is too far so that PC-REL
cannot be accessed directly, only GOT.

When compiling module with GCC, the option `-mdirect-extern-access` is
disabled by default. The Clang option `-fdirect-access-external-data` is
enabled by default, so it needs to be explicitly disabled.
Signed-off-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Makefile

@@ -68,6 +68,8 @@ LDFLAGS_vmlinux			+= -static -n -nostdlib
 ifdef CONFIG_AS_HAS_EXPLICIT_RELOCS
 cflags-y			+= $(call cc-option,-mexplicit-relocs)
 KBUILD_CFLAGS_KERNEL		+= $(call cc-option,-mdirect-extern-access)
+KBUILD_AFLAGS_MODULE		+= $(call cc-option,-fno-direct-access-external-data)
+KBUILD_CFLAGS_MODULE		+= $(call cc-option,-fno-direct-access-external-data)
 KBUILD_AFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
 KBUILD_CFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
 else