clk: qcom: rpmh: Simplify clk_rpmh_bcm_send_cmd()

[ Upstream commit 2cf7a4cbcb4e108aae666dc6a81cedf69e1cba37 ]

This function has some duplication in unlocking a mutex and returns in a
few different places. Let's use some if statements to consolidate code
and make this a bit easier to read.

Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
CC: Taniya Das <tdas@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20200309221232.145630-2-sboyd@kernel.org


Stable-dep-of: a4e5af27e6f6 ("clk: qcom: clk-rpmh: Fix overflow in BCM vote")
Signed-off-by: Sasha Levin <sashal@kernel.org>