msm:clock-8974: Add suspend/resume support for DSI PLL

The resume routine never calls set_rate for the same clock rate.
Since DSI PHY register values will be reset during suspend/resume,
add support to re-initialize the DSI PHY PLL during resume sequence.

Change-Id: I0106b4910d6081de5697f64ea07fd5eab718f5e2
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>