usb: dwc3-msm: Fix GDSC collapse in host mode bus suspend

Commit f8d9e7b72edb (usb: dwc3-msm: Collapse GDSC in host mode
bus suspend) added GDSC power collapse in host mode bus suspend.
As part of GDSC power collapse driver is also setting
MDWC3_POWER_COLLAPSE flag. So when bus resume happens driver will
perform a core reset which resets the peripherals connected to the
host. This bus reset leads to re-enumeration of the peripherals.
This change collapses GDSC as part of host mode bus suspend but
doesn't sets MDWC3_POWER_COLLAPSE flag.

Change-Id: I066b8f5b1163a5dad7dd00831e42594715e65798
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>