usb: ehci-orion: enable big-endian support

This commit fixes ehci-orion operation in big-endian mode by enabling byteswap
when accessing registers using 'rdl' and 'wrl' macros.

Signed-off-by: Grzegorz Jaszczyk <jaz@semihalf.com>
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>