clk: qcom: Add Q6SSTOP clock controller for QCS404

Add support for the Q6SSTOP clock control used on qcs404
based devices. This would allow wcss remoteproc driver to
control the required WCSS Q6SSTOP clock/reset controls to
bring the subsystem out of reset and shutdown the WCSS Q6DSP.

Signed-off-by: Govind Singh <govinds@codeaurora.org>
Link: https://lkml.kernel.org/r/20191011132928.9388-3-govinds@codeaurora.org
[sboyd@kernel.org: Sort makefile]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>