dwc3: gadget: Initiate remote wakeup only if configuration allows

Gadget driver initiates remote wakeup after bus suspend even if
current configuration of device does not support it. As a result
functions like diag queue the request at bus suspend during
disconnect. This causes page fault exception while traversing
config->functions list in composite_resume() when unbind_config()
is racing with it as part of disconnect. Hence check remote_wakeup
flag before initiating the remote wakeup after bus suspend.
remote_wakeup flag is set to true when host issues set
feature remote wakeup before doing bus suspend in case of high,
full, low speed.

CRs-Fixed: 755939
Change-Id: Ic26a1542896667b36e14fc65c6d3646953672197
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>