clk: msm: clock-cpu: Add a new boolean property for PM Qos

Support "qcom,enable-qos" property which is required when the cpu clocks
require to request a pm qos value while updating the PLL and root clock
generator during clock set rate.

CRs-Fixed: 973895
Change-Id: I3254f68a001ded267a3b0eb7934e1c8233463255
Signed-off-by: Taniya Das <tdas@codeaurora.org>