time/posix-stubs: Provide compat itimer supoprt for alpha

Using compat_sys_getitimer and compat_sys_setitimer on alpha
causes a link failure in the Alpha tinyconfig and other configurations
that turn off CONFIG_POSIX_TIMERS.

Use the same #ifdef check for the stub version as well.

Fixes: 4c22ea2 ("y2038: use compat_{get,set}_itimer on alpha")
Reported-by: Guenter Roeck <[email protected]>
Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: arndb

kernel/time/posix-stubs.c

@@ -151,6 +151,9 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYS_NI(timer_create);
+#endif
+
+#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
 COMPAT_SYS_NI(getitimer);
 COMPAT_SYS_NI(setitimer);
 #endif