[media] staging/media: fix go7007 dependencies and build

VIDEO_GO7007 uses usb interfaces so it should depend on USB.
It also selects CYPRESS_FIRMWARE, which depends on USB.
Fixes build errors and a kconfig warning:
go7007-loader.c:(.text+0xcc7d0): undefined reference to `usb_get_dev'
go7007-loader.c:(.init.text+0x49f0): undefined reference to `usb_register_driver'
go7007-loader.c:(.exit.text+0x17ce): undefined reference to `usb_deregister'
warning: (DVB_USB_AZ6007 && VIDEO_GO7007) selects CYPRESS_FIRMWARE which has unmet direct dependencies (MEDIA_SUPPORT && USB)
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/staging/media/go7007/Kconfig

 config VIDEO_GO7007
 	tristate "WIS GO7007 MPEG encoder support"
 	depends on VIDEO_DEV && I2C
-	depends on SND
+	depends on SND && USB
 	select VIDEOBUF2_VMALLOC
 	select VIDEO_TUNER
 	select CYPRESS_FIRMWARE