[PATCH] i386: fix prevent_tail_call

We fixed this bug before, but it didn't take.  It may have been the case
that the problem was first noticed to occur in a CONFIG_REGPARM compile.
But it's not regparm functions that need not to make tail calls, it's
asmlinkage functions called with a user pt_regs frame on the stack
supplying their arguments.  prevent_tail_call probably doesn't do anything
at all in regparm functions (your argument registers are going to be
clobbered, period).  It was a braino to conditionalize that definition in
the first place.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-i386/linkage.h

@@ -5,9 +5,7 @@
 #define FASTCALL(x)	x __attribute__((regparm(3)))
 #define fastcall	__attribute__((regparm(3)))
 
-#ifdef CONFIG_REGPARM
-# define prevent_tail_call(ret) __asm__ ("" : "=r" (ret) : "0" (ret))
-#endif
+#define prevent_tail_call(ret) __asm__ ("" : "=r" (ret) : "0" (ret))
 
 #ifdef CONFIG_X86_ALIGNMENT_16
 #define __ALIGN .align 16,0x90