ARM64: dts: qcom: Add clock properties to GDSC on MSM8994

Some GDSCs need to manipulate clock states when powering on/off
their power domains. Add corresponding clock properties to device tree
node.

Change-Id: I71f86771126242613a17c141899883da01c3c95a
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>