clk: qcom: Remove GPU CC RBCPR clock support on SDM845

The clock is enabled by XBL and it will be gated by HW
when the GFX rail goes retention or power off.

CRs-Fixed: 2051367
Change-Id: I3707c1d1e29f3d47977f6b4354de783e5d8f53a1
Signed-off-by: Vicky Wallace <vwallace@codeaurora.org>