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

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

Change-Id: I77e932413711121c5fab63d9b3436390b9f8014c
Signed-off-by: Madhuri Medasani <mmedasan@codeaurora.org>