rtc: efi: Remove wakeup functionality

The EFI rtc driver is used by non-x86 architectures only, and exposes
the get/set wakeup time functionality provided by the underlying
platform. This is usually broken on most platforms, and not widely used
to begin with [if at all], so let's just remove it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Feng Tang <feng.tang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250714060843.4029171-6-ardb+git@google.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>