y2038: signal: Change rt_sigtimedwait to use __kernel_timespec

This changes sys_rt_sigtimedwait() to use get_timespec64(), changing
the timeout type to __kernel_timespec, which will be changed to use
a 64-bit time_t in the future. Since the do_sigtimedwait() core
function changes, we also have to modify the compat version of this
system call in the same way.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index fb3a05f..2ac3d13 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -635,7 +635,7 @@ asmlinkage long sys_rt_sigprocmask(int how, sigset_t __user *set,
 asmlinkage long sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize);
 asmlinkage long sys_rt_sigtimedwait(const sigset_t __user *uthese,
 				siginfo_t __user *uinfo,
-				const struct timespec __user *uts,
+				const struct __kernel_timespec __user *uts,
 				size_t sigsetsize);
 asmlinkage long sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo);