MIPS: include: Mark __cmpxchg as __always_inline

Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") allows compiler to uninline functions marked as 'inline'.
In cace of cmpxchg this would cause to reference function
__cmpxchg_called_with_bad_pointer, which is a error case
for catching bugs and will not happen for correct code, if
__cmpxchg is inlined.

Signed-off-by: Thomas Bogendoerfer <[e-mail]>
[[e-mail]: s/__cmpxchd/__cmpxchg in subject]
Signed-off-by: Paul Burton <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]

arch/mips/include/asm/cmpxchg.h

···
 extern unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old,
 				     unsigned long new, unsigned int size);
 
-static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
-				      unsigned long new, unsigned int size)
+static __always_inline
+unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+			unsigned long new, unsigned int size)
 {
 	switch (size) {
 	case 1: