usb: gadget: f_mass_storage: remove one FSG_NO_INTR_EP

Remove one define of FSG_NO_INTR_EP and we still have that we can use.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>