USB: gadget: gadget_is_{dualspeed,otg} predicates and cleanup

This adds two small inlines to the gadget stack, which will
often evaluate to compile-time constants.  That can help
shrink object code and remove #ifdeffery.

 - gadget_is_dualspeed(), currently always a compile-time
   constant (depending on which controller is selected).

 - gadget_is_otg(), usually a compile time "false", but this
   is a runtime test if the platform enables OTG (since it's
   reasonable to populate boards with different USB sockets).

It also updates two peripheral controller drivers to use these:

 - fsl_usb2_udc, mostly OTG-related bugfixes:  non-OTG devices
   must follow the rules about drawing VBUS power, and OTG ones
   need to reject invalid SET_FEATURE requests.

 - omap_udc, just scrubbing a bit of #ifdeffery.

And also gadgetfs, which lost some #ifdefs and moved to a more
standard handling of DEBUG and VERBOSE_DEBUG.

The main benefits come from patches which will follow.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/omap_udc.c b/drivers/usb/gadget/omap_udc.c
index 9b0f092..bf2788d 100644
--- a/drivers/usb/gadget/omap_udc.c
+++ b/drivers/usb/gadget/omap_udc.c
@@ -1241,19 +1241,15 @@
 	udc->gadget.dev.parent->power.power_state = PMSG_ON;
 	udc->gadget.dev.power.power_state = PMSG_ON;
 	UDC_SYSCON1_REG |= UDC_PULLUP_EN;
-#ifndef CONFIG_USB_OTG
-	if (!cpu_is_omap15xx())
+	if (!gadget_is_otg(udc->gadget) && !cpu_is_omap15xx())
 		OTG_CTRL_REG |= OTG_BSESSVLD;
-#endif
 	UDC_IRQ_EN_REG = UDC_DS_CHG_IE;
 }
 
 static void pullup_disable(struct omap_udc *udc)
 {
-#ifndef CONFIG_USB_OTG
-	if (!cpu_is_omap15xx())
+	if (!gadget_is_otg(udc->gadget) && !cpu_is_omap15xx())
 		OTG_CTRL_REG &= ~OTG_BSESSVLD;
-#endif
 	UDC_IRQ_EN_REG = UDC_DS_CHG_IE;
 	UDC_SYSCON1_REG &= ~UDC_PULLUP_EN;
 }
@@ -1390,7 +1386,7 @@
 {
 	u16	devstat;
 
-	if (!udc->gadget.is_otg)
+	if (!gadget_is_otg(udc->gadget))
 		return;
 
 	if (OTG_CTRL_REG & OTG_ID)