usb: gadget: Remove circular dependency on Config

drivers/usb/gadget/Kconfig:208:error: recursive dependency detected!
drivers/usb/gadget/Kconfig:208: choice <choice> contains symbol
USB_CONFIGFS_F_MIDI
drivers/usb/gadget/Kconfig:434: symbol USB_CONFIGFS_F_MIDI depends on
USB_CONFIGFS
drivers/usb/gadget/Kconfig:229: symbol USB_CONFIGFS is part of choice <choice>

BUG: 24606128

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Change-Id: I70a1bbca4ff7371a4d3a50285673a0845dbdcb10