msm: kgsl: Add the oxili_rbbmtimer_clk to the list of gpu clks

The oxili_rbbmtimer_clk needs to be enabled to take advantage of
the RBBM_ALWAYSON_COUNTER. Add this clk to this list of gpu clks
being enabled.

Change-Id: I39ab1922dc02df96e4cf3c2472d4a24b6cc612d0
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>