musb: sunxi: Remove custom babble handling

The musb core already handles babble interrupts, so the sunxi glue
having its own custom handling is redundant.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>