usb: gadget: Introduce handle_interrupts ops to USB_GADGET_GENERIC uclass

usb: gadget: Introduce handle_interrupts ops to USB_GADGET_GENERIC uclass

Introduce .ops for USB_GADGET_GENERIC uclass. The first new ops is
.handle_interrupts which must be implemented by DM capable USB gadget
controller drivers and must implement interrupt handling similar to
dm_usb_gadget_handle_interrupts(). This patch currently provides weak
dm_usb_gadget_handle_interrupts() implementation which is overridden by
the drivers, but this will be removed once conversion to handle_interrupts
callback is complete.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # vim3
Link: https://lore.kernel.org/r/20240614005309.34433-2-marek.vasut+renesas@mailbox.org
[mkorpershoek: fixed trivial typo in commit message]
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>