clk: qcom: Add ipq6018 apss clock controller

The CPU on Qualcomm ipq6018 devices are clocked primarily by a aplha PLL
and xo which are connected to a mux and enable block.

Add support for the mux and enable block which feeds the CPU on ipq6018
devices.

Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Link: https://lore.kernel.org/r/1592800092-20533-5-git-send-email-sivaprak@codeaurora.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>