usb: musb: be careful when using different fifo_modes

if we have more endpoints configured than
enabled on fifo_mode, then we need to be
careful on save/restore context operations,
otherwise we will try to access uninitialized
__iomem pointer.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_core.c

@@ -2214,7 +2214,16 @@ static void musb_save_context(struct musb *musb)
 	musb->context.devctl = musb_readb(musb_base, MUSB_DEVCTL);
 
 	for (i = 0; i < musb->config->num_eps; ++i) {
-		epio = musb->endpoints[i].regs;
+		struct musb_hw_ep	*hw_ep;
+
+		hw_ep = &musb->endpoints[i];
+		if (!hw_ep)
+			continue;
+
+		epio = hw_ep->regs;
+		if (!epio)
+			continue;
+
 		musb->context.index_regs[i].txmaxp =
 			musb_readw(epio, MUSB_TXMAXP);
 		musb->context.index_regs[i].txcsr =
@@ -2280,7 +2289,16 @@ static void musb_restore_context(struct musb *musb)
 	musb_writeb(musb_base, MUSB_DEVCTL, musb->context.devctl);
 
 	for (i = 0; i < musb->config->num_eps; ++i) {
-		epio = musb->endpoints[i].regs;
+		struct musb_hw_ep	*hw_ep;
+
+		hw_ep = &musb->endpoints[i];
+		if (!hw_ep)
+			continue;
+
+		epio = hw_ep->regs;
+		if (!epio)
+			continue;
+
 		musb_writew(epio, MUSB_TXMAXP,
 			musb->context.index_regs[i].txmaxp);
 		musb_writew(epio, MUSB_TXCSR,