usb: gadget: Fix crash on calling usb gadget activate/deactivate

Currently the functions usb_gadget_activate and
usb_gadget_deactivate are being called with spinlock held.
The above functions calls gadget_pullup which invokes
pm_runtime_get_sync call, which might sleep.
This results in a crash. Fix this by releasing the
spinlock and acquiring it after the function call.

Change-Id: I17359e3c3227773a8ce269f8db93bc1d56771044
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>