usb: dwc2: host: don't clear hprt0 status bits when exiting hibernation

When entering hibernation hprt0 must be read using dwc2_read_hprt0().
Otherwise, any set hprt0 status bits will be cleared when restoring
hprt0 on exit from hibernation.

Signed-off-by: Gregory Herrero <gregory.herrero@intel.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Tested-by: John Youn <johnyoun@synopsys.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>