drivers: llcc: Add extra check for sct size during get slice call

There could be a potential out of bound access to the sct table, if
client calls get slice with not supported slice id.
So to avoid the same check the size of sct table to traverse and
return error in case slice id is not present.

Change-Id: I39f4a61dd46e0e8b65b827b63073e1d6f0f2ca24
Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>