USB: dwc3-msm: Allow XO shutdown in HOST mode bus suspend

In HOST bus suspend utmi-clk can also be turned off which
is used for ITP/SOF generation and not required in suspend.
Doing this would allow us to support XO shutdown in host mode
bus suspend.
Since, master_clk is left ON in SS bus suspend due to hardare
limitation XO shutdown would happen only if SS session is not
active i.e. when no USB device or only a HIGH speed USB device
is connected to host port.

Change-Id: I4924c0c0df20467c80e52046ea13a437fa71b87e
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>