ARM: pxa: drop gpio_vbus field from pxa2xx_udc_mach_info

Neither pxa25x_udc, nor pxa27x_udc use gpio_vbus/gpio_vbus_inverted
anymore. Drop those two fields from udc info completely.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>