morello: enable automatic sampling and temperature interrupts

This patch enables the following features in the morello_sensor driver:

1. Hardware driven periodic sampling of temperature and voltage sensors.
2. Alarm A and B for temperature sensor and interrupt handling
   for the same.

Signed-off-by: sahil <sahil@arm.com>
Change-Id: I95bd916984c77bcb008d72bf9840d231988afb41