clk: qcom: Enable clocks which needs to be always on for SDM845

There are certain clocks which needs to be always enabled for system
operation. Add support for the same by adding 'CLK_IS_CRITICAL' flag
for such clocks.

Signed-off-by: Amit Nischal <anischal@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>