usb: gadget: gsi: Fix reporting of USB device's usage count

Currently driver is reading and logging usage count of gadget
device but it is required to use usage count of gadget's parent
device which is used to prevent USB controller's low power mode.
Hence fix reporting of USB devices' usage count.

Also mark sm_state to initialized and remove queueing of
ipa_usb_wq as ipa_work_handler() is running without USB gadget
is initialized i.e. gadget is NULL.

CRs-Fixed: 1021499
Change-Id: Ia64afa3adb769674f6a9a60fde2c7397b7e4fe49
Signed-off-by: Mayank Rana <mrana@codeaurora.org>