dt-bindings: clock: Add support for clock ids for SCUBA

Add clock IDs for GCC/GPUCC/DISPCC for clients to be able
to request for clocks from these clock controllers.

Change-Id: Ibd69e800ff6ebd0d59d34605deb8dc092c25b907
Signed-off-by: Hongwei Ren <hongren@codeaurora.org>