switch compat_sys_sigprocmask to COMPAT_SYSCALL_DEFINE

In principle, C ABI violation on ppc and mips...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/compat.c b/kernel/compat.c
index 460e98f..a53b04a 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -381,9 +381,9 @@
 	memcpy(blocked->sig, &set, sizeof(set));
 }
 
-asmlinkage long compat_sys_sigprocmask(int how,
-				       compat_old_sigset_t __user *nset,
-				       compat_old_sigset_t __user *oset)
+COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
+		       compat_old_sigset_t __user *, nset,
+		       compat_old_sigset_t __user *, oset)
 {
 	old_sigset_t old_set, new_set;
 	sigset_t new_blocked;