usb: dwc2/gadget: delay enabling irq once hardware is configured properly

usb: dwc2/gadget: delay enabling irq once hardware is configured properly

commit eb3c56c5ccdd252940cb0ec0541fcdc94894bd8d upstream.

This patch fixes kernel panic/interrupt storm/etc issues if bootloader
left s3c-hsotg module in enabled state. Now interrupt handler is enabled
only after proper configuration of hardware registers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>