MIPS: include: Mark __xchg as __always_inline

Commit ac7c3e4 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") allows compiler to uninline functions marked as 'inline'.
In cace of __xchg this would cause to reference function
__xchg_called_with_bad_pointer, which is an error case
for catching bugs and will not happen for correct code, if
__xchg is inlined.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

arch/mips/include/asm/cmpxchg.h

@@ -77,8 +77,8 @@ 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(volatile void *ptr, unsigned long x,
-				   int size)
+static __always_inline
+unsigned long __xchg(volatile void *ptr, unsigned long x, int size)
 {
 	switch (size) {
 	case 1: