USB: fsl_usb2_udc: Get max ep number from DCCPARAMS register

Currently the driver is expecting max ep number in platform
data which isn't passing this information.  This patch fix
the problem by reading it from DCCPARAMS(Device Controller
Capability Parameters) register.  The change also need some
reordering of the probe code.

Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>