plat/arm/sgi: fix the incorrect check for SCMI channel ID

Use ARRAY_SIZE macro instead of sizeof operator to obtain the maximum
number of SCMI channels supported on the platform.

Change-Id: Id922bb548af98ac99b4ac0c34e38e589e5a80b2d
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>
1 file changed