usb: usb bam: release spin lock before calling sps_device_reset

Change 'b215cdcc' "usb: usb_bam: add bam global inactivity and activity
notifications" has introduced a bug in which sps_device_reset is called
while spin lock is held, fix this by releasing the spin lock before
calling the sps_device reset.

Change-Id: Idef76ca9d18c2e43333f53cea96c5d8e76a1a563
Signed-off-by: Ido Shayevitz <idos@codeaurora.org>