[PATCH] reorder 'rep;nop;' in the spinlock macro

According to Intel's recommendation, 'rep;nop; should be called before
testing if the lock variable was modified (i.e. rep nop;cmp;jcc). The
current implementation does it the wrong way around: first test, then
wait, then branch. I've asked Asit Mallik from Intel, and he recommended
to change it.

It should be at least consistent: Right now, spinlock uses
'cmp;rep nop;jcc', rwlock uses 'rep nop;cmp;jcc'

include/asm-i386/spinlock.h

@@ -48,8 +48,8 @@ typedef struct {
 	"js 2f\n" \
 	LOCK_SECTION_START("") \
 	"2:\t" \
-	"cmpb $0,%0\n\t" \
 	"rep;nop\n\t" \
+	"cmpb $0,%0\n\t" \
 	"jle 2b\n\t" \
 	"jmp 1b\n" \
 	LOCK_SECTION_END