alpha-linux-user: Fix sigsuspend parameters.

Alpha passes the signal set in a register, not by reference.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e9e61c8..fb18b24 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5088,10 +5088,15 @@
     case TARGET_NR_sigsuspend:
         {
             sigset_t set;
+#if defined(TARGET_ALPHA)
+            abi_ulong mask = arg1;
+            target_to_host_old_sigset(&set, &mask);
+#else
             if (!(p = lock_user(VERIFY_READ, arg1, sizeof(target_sigset_t), 1)))
                 goto efault;
             target_to_host_old_sigset(&set, p);
             unlock_user(p, arg1, 0);
+#endif
             ret = get_errno(sigsuspend(&set));
         }
         break;