MIPS: set mips32r5 for virt extensions

Clang's integrated assembler only accepts these instructions when the
cpu is set to mips32r5. With this change, we can assemble
malta_defconfig with Clang via `make LLVM_IAS=1`.

Link: https://github.com/ClangBuiltLinux/linux/issues/763
Reported-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/mipsregs.h

@@ -2077,7 +2077,7 @@ _ASM_MACRO_0(tlbginvf, _ASM_INSN_IF_MIPS(0x4200000c)
 ({ int __res;								\
 	__asm__ __volatile__(						\
 		".set\tpush\n\t"					\
-		".set\tmips32r2\n\t"					\
+		".set\tmips32r5\n\t"					\
 		_ASM_SET_VIRT						\
 		"mfgc0\t%0, " #source ", %1\n\t"			\
 		".set\tpop"						\
@@ -2090,7 +2090,7 @@ _ASM_MACRO_0(tlbginvf, _ASM_INSN_IF_MIPS(0x4200000c)
 ({ unsigned long long __res;						\
 	__asm__ __volatile__(						\
 		".set\tpush\n\t"					\
-		".set\tmips64r2\n\t"					\
+		".set\tmips64r5\n\t"					\
 		_ASM_SET_VIRT						\
 		"dmfgc0\t%0, " #source ", %1\n\t"			\
 		".set\tpop"						\
@@ -2103,7 +2103,7 @@ _ASM_MACRO_0(tlbginvf, _ASM_INSN_IF_MIPS(0x4200000c)
 do {									\
 	__asm__ __volatile__(						\
 		".set\tpush\n\t"					\
-		".set\tmips32r2\n\t"					\
+		".set\tmips32r5\n\t"					\
 		_ASM_SET_VIRT						\
 		"mtgc0\t%z0, " #register ", %1\n\t"			\
 		".set\tpop"						\
@@ -2115,7 +2115,7 @@ do {									\
 do {									\
 	__asm__ __volatile__(						\
 		".set\tpush\n\t"					\
-		".set\tmips64r2\n\t"					\
+		".set\tmips64r5\n\t"					\
 		_ASM_SET_VIRT						\
 		"dmtgc0\t%z0, " #register ", %1\n\t"			\
 		".set\tpop"						\