usb: dwc3-msm: Collapse GDSC in host mode bus suspend

Currently driver is not turning off GDSC regulator as part of
LPM entry in host mode bus suspend. There is a requirement to
collapse GDSC as well to allow controller collapse in host mode
bus suspend.

Change-Id: I898553fbfb2c7931046d838a66abf8d9e7b72edb
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>