clk: msm: clock-gcc-cobalt: Add cxo as bimc_clk parent

XO shutdown should not happen when there's still a sleep
vote on DDR. Making CXO as bimc_clk parent takes care of
this.

CRs-Fixed: 992753
Change-Id: I49ac2aefb645a4463cb1873072cd3a1f9a136dad
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>