usb: gadget: s3c-hsotg: fix disconnect handling

This patch moves s3c_hsotg_disconnect function call from USBSusp interrupt
handler to SET_ADDRESS request handler.

It's because disconnected state can't be detected directly, because this
hardware doesn't support Disconnected interrupt for device mode. For both
Suspend and Disconnect events there is one interrupt USBSusp, but calling
s3c_hsotg_disconnect from this interrupt handler causes config reset in
composite layer, which is not undesirable for Suspended state.

For this reason s3c_hsotg_disconnect is called from SET_ADDRESS request
handler, which occurs always after disconnection, so we do disconnect
immediately before we are connected again. It's probably only way we
can do handle disconnection correctly.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>