staging: emxx_udc: Use standard BIT() macro

Currently emxx_udc.h defines bit values using local macros. Use the
standard one instead.

Also, combine bit values with bitwise-or rather than addition, as
suggested by Coccinelle.
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Link: https://lore.kernel.org/r/20200818134922.409195-1-alex.dewar90@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>