alpha-linux-user: Properly handle the non-rt sigprocmask syscall.

Name the syscall properly for QEMU, kernel source notwithstanding.
Fix syntax errors in the code thus enabled within do_syscall.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 07823e1..0d3fff5 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5881,11 +5881,10 @@
             target_to_host_old_sigset(&set, &mask);
 
             ret = get_errno(sigprocmask(how, &set, &oldset));
-
             if (!is_error(ret)) {
                 host_to_target_old_sigset(&mask, &oldset);
                 ret = mask;
-                ((CPUAlphaState *)cpu_env)->[IR_V0] = 0; /* force no error */
+                ((CPUAlphaState *)cpu_env)->ir[IR_V0] = 0; /* force no error */
             }
 #else
             sigset_t set, oldset, *set_ptr;