usb: dwc3: Remove toggling of HSPHY autosuspend

There have been issues related to having the GUSB2PHYCFG_SUSPHY bit
set which may cause problems with controller commands timing out in
both peripheral and host modes. Instead of working around this by
toggling it off and on as needed, simply disable it whenever the
controller is not in low power mode. The only place where it will be
set is just prior to entering suspend and cleared just after exiting.

This patch effectively reverts the following:
commit e1e8f22e "USB: dwc3: Clear USB2PHY_SUSP bit during disconnect"
commit 02b09d2b "USB: dwc3: msm: Fix stop endpoint command timeout issue"
commit 438c0416 "usb: dwc3: Add support to disable hsphy auto suspend
feature"

Change-Id: Iaa5274dbfaf2d3ab243e030f09510bdbad72616e
Signed-off-by: Jack Pham <jackp@codeaurora.org>