usb: musb_core: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 1397608
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -767,6 +767,7 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 		case OTG_STATE_B_IDLE:
 			if (!musb->is_active)
 				break;
+			/* fall through */
 		case OTG_STATE_B_PERIPHERAL:
 			musb_g_suspend(musb);
 			musb->is_active = musb->g.b_hnp_enable;