alpha: wire up accept4 syscall

Somehow wiring up the accept4 syscall on Alpha was missed long ago.
This commit rectifies that oversight.

Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/alpha/include/asm/unistd.h b/arch/alpha/include/asm/unistd.h
index 4ac48a0..1fbfd64 100644
--- a/arch/alpha/include/asm/unistd.h
+++ b/arch/alpha/include/asm/unistd.h
@@ -457,10 +457,11 @@
 #define __NR_clock_adjtime		499
 #define __NR_syncfs			500
 #define __NR_setns			501
+#define __NR_accept4			502
 
 #ifdef __KERNEL__
 
-#define NR_SYSCALLS			502
+#define NR_SYSCALLS			503
 
 #define __ARCH_WANT_IPC_PARSE_VERSION
 #define __ARCH_WANT_OLD_READDIR