usb: mv_udc: Move endpoint array into driver data

The endpoints are operated on a per-controller basis, move the
endpoint array into controller's private data. Also shuffle the
struct mv_ep structure definition just above the definition of
the struct mv_drv so they're well grouped together.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Lei Wen <leiwen@marvell.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>