kernel: clean up usb gadget support

clean up usb gadget support:
- rename gadget modules so that they appear together and are easier to
  identify as gadget modules
- make usb-lib-composite and usb-gadget hidden as there is no point in
  selecting those without gadget drivers that require them as deps

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

target/linux/at91/Makefile

@@ -17,6 +17,6 @@ KERNEL_PATCHVER:=4.4
 
 include $(INCLUDE_DIR)/target.mk
 
-DEFAULT_PACKAGES += kmod-usb-ohci kmod-at91-udc kmod-usb-eth-gadget
+DEFAULT_PACKAGES += kmod-usb-ohci kmod-at91-udc kmod-usb-gadget-eth
 
 $(eval $(call BuildTarget))

target/linux/omap24xx/profiles/100-n810.mk

@@ -16,7 +16,7 @@ define Profile/n810-base
 	kmod-fs-vfat kmod-fs-msdos \
 	kmod-input-evdev \
 	kmod-leds-gpio \
-	kmod-usb-tahvo kmod-usb-eth-gadget \
+	kmod-usb-tahvo kmod-usb-gadget-eth \
 	kmod-usb-net kmod-usb-net-cdc-ether kmod-usb-net-pegasus kmod-usb-net-rndis \
 	kmod-usb-storage kmod-usb-hid \
 	kmod-bluetooth kmod-bluetooth-hci-h4p bluez-utils bluez-hcidump \