scsi: ufs-qcom: Refactor phy_power_on/off calls

Commit 052553af ("ufs/phy: qcom: Refactor to use phy_init call") puts
enabling regulators & clks, calibrating UFS PHY, starting serdes and
polling PCS ready status into phy_power_on.

Due to UFS PHY's registers are retained after power collapse, so
calibrating UFS PHY, starting serdes and polling PCS ready status need to
be done only when start hba, but not needed every time when phy_power_on
is called during resume. Keep the codes which enables PHY's regulators &
clks in phy_power_on but move the rest steps into PHY's general calibration
func, namely phy_calibrate.

Commit 3f6d1767 ("phy: ufs-qcom: Refactor all init steps into
phy_poweron") removes the phy_power_on/off from ufs_qcom_setup_clocks.

To have a better power saving, remove the phy_power_on/off calls from
resume/suspend path and put them back to ufs_qcom_setup_clocks, so that
PHY's regulators & clks can be turned on/off along with UFS's clocks.

At last, add a mutex lock to protect the usage of is_phy_pwr_on against
possible racing.

Change-Id: I1ed5d5d6968c3f16018e9723eab010ea7ed798b2
Signed-off-by: Can Guo <cang@codeaurora.org>