[ARM] 2952/1: fix a register clobber list

Patch from Nicolas Pitre

If gcc decides to assign lr to %0 we're screwed.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/sys_arm.c

@@ -305,7 +305,7 @@ long execve(const char *filename, char **argv, char **envp)
 		  "Ir" (THREAD_START_SP - sizeof(regs)),
 		  "r" (&regs),
 		  "Ir" (sizeof(regs))
-		: "r0", "r1", "r2", "r3", "ip", "memory");
+		: "r0", "r1", "r2", "r3", "ip", "lr", "memory");
 
  out:
 	return ret;