drm/msm: Corrected CCU load bit configuration

CCU load_bit is supposed to be configured for RB_PERFCTR_CCU register, but
it is configured for RB_POWERCTR_CCU register. Updated the RB_PERFCTR_CCU
register configuration with CCU load_bit.

Change-Id: I3b4ce056923b5bd39bc274a0744008f5bc5db0f1
Signed-off-by: Venkateswara Rao Tadikonda <vtadik@codeaurora.org>