hwmon: (xgene) Migrate to use generic PCC shmem related macros

Use the newly defined common and generic PCC shared memory region
related macros in this driver to replace the locally defined ones.

Cc: Jean Delvare <jdelvare@suse.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230927-pcc_defines-v2-3-0b8ffeaef2e5@arm.com


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>