drivers: cci: Extend support to CCI revisions > r1p2

The driver queries the CCI IP revision to distinguish between r0 and r1
scheme for event numbers and currently supports upto version r1p2. To
minimise code churn every time there's a new version of the IP, assume
that event numbering doesn't change for revisions > r1p0 (which is
the case).

The driver will still need an update for future revisions that change
the event numbers.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>