phy: qcom-snps: Add runtime suspend and resume handlers

Allow for the PHY to be put into a powered down state when possible.
Add the required suspend and resume callbacks, which will determine
what resources can be turned off depending on the cable status.

Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
Link: https://lore.kernel.org/r/20200625195444.15130-2-wcheng@codeaurora.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>