platform/x86: amd-pmc: Drop check for valid alarm time

This is already checked when calling rtc_read_alarm.

Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20211026171443.289-3-mario.limonciello@amd.com


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>