clk: msm: clock-gcc-8998: keep gcc_bimc_gfx_clk on

Keep gcc_bimc_gfx_clk always on to prevent a stall during BIMC
redirection handshake that occurs as part of a transition between
different CCI power modes. The stall causes momentary bandwidth drops
for the display ports and creates display buffer underflows.

Change-Id: Ie7de487fbe16c7e6b1234a96c1208d54daa5a9bb
Signed-off-by: David Dai <daidavid1@codeaurora.org>