[PATCH] m32r: __cmpxchg_u32 fix

This patch fixes a bug of include/asm-m32r/system.h:__cmpxchg_u32().

  static __inline__ unsigned long
  __cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new);

In __cmpxchg_u32(), the "old" value must not be changed to the previous "*p"
value.  But the former code modifies the previous "*p" value.

A deadlock at _atomic_dec_and_lock sometimes happened due to this bug.
Signed-off-by: NHayato Fujiwara <fujiwara@linux-m32r.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/asm-m32r/system.h

@@ -239,7 +239,7 @@ __cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new)
 		"	bra	2f;		\n"
                 "       .fillinsn		\n"
 		"1:"
-			M32R_UNLOCK" %2, @%1;	\n"
+			M32R_UNLOCK" %0, @%1;	\n"
                 "       .fillinsn		\n"
 		"2:"
 			: "=&r" (retval)