MIPS: cmpxchg: Rearrange __xchg() arguments to match xchg()

The __xchg() function declares its first 2 arguments in reverse order
compared to the xchg() macro, which is confusing & serves no purpose.
Reorder the arguments such that __xchg() & xchg() match.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16356/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/cmpxchg.h

@@ -73,7 +73,8 @@ extern unsigned long __xchg_called_with_bad_pointer(void)
 extern unsigned long __xchg_small(volatile void *ptr, unsigned long val,
 				  unsigned int size);
 
-static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
+static inline unsigned long __xchg(volatile void *ptr, unsigned long x,
+				   int size)
 {
 	switch (size) {
 	case 1:
@@ -101,7 +102,7 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
 	smp_mb__before_llsc();						\
 									\
 	__res = (__typeof__(*(ptr)))					\
-		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)));	\
+		__xchg((ptr), (unsigned long)(x), sizeof(*(ptr)));	\
 									\
 	smp_llsc_mb();							\
 									\