msm: pcie: add locks to protect PCIe common PHY init and deinit

The counter for the number of active root complexes
determines when PCIe common PHY should be powered on/off.
To avoid conflicts and a stale counter, add locks to protect
the access to PCIe common PHY.

Change-Id: I18ec54e52e804eb132f9c5c0270455dbc9187151
Signed-off-by: Tony Truong <truong@codeaurora.org>