blackfin: don't open-code force_sigsegv()

... especially since we don't have the right k_sigaction here,
so resetting sa_handler won't work.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c
index 05ece02..e5bbc1a 100644
--- a/arch/blackfin/kernel/signal.c
+++ b/arch/blackfin/kernel/signal.c
@@ -210,9 +210,7 @@
 	return 0;
 
  give_sigsegv:
-	if (sig == SIGSEGV)
-		ka->sa.sa_handler = SIG_DFL;
-	force_sig(SIGSEGV, current);
+	force_sigsegv(sig, current);
 	return -EFAULT;
 }