USB: pxa27x_udc: minor fixes

Minor fixes to pxa27x udc driver :
 - don't clobber driver model bus_id field
 - wrong endianess fix (no functional change; cpu is little-endian)
 - double udc disable fix
 - resume/suspend fix (OTG hold bit)
 - make driver pxa27x dependant (check cpu at runtime)

Signed-off-by: Robert Jarzmik <rjarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>