C6X: clean up compiler warning

commit a610d6e6: pull clearing RESTORE_SIGMASK into block_sigmask()
left behind a compiler warning:

  arch/c6x/kernel/signal.c:252:6: warning: unused variable 'ret'

This patch cleans up the warning by removing the unused variable.
Signed-off-by: Mark Salter <msalter@redhat.com>

arch/c6x/kernel/signal.c

@@ -249,8 +249,6 @@ static void handle_signal(int sig,
 			 siginfo_t *info, struct k_sigaction *ka,
 			 struct pt_regs *regs, int syscall)
 {
-	int ret;
-
 	/* Are we from a system call? */
 	if (syscall) {
 		/* If so, check system call restarting.. */