staging: emxx_udc: Allow for building on !ARM

Currently the module can only be test built on ARM, although it seems to
build fine on x86. Change this to allow for broader test coverage.

Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Link: https://lore.kernel.org/r/20200818151133.583382-1-alex.dewar90@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>