greybus: es2: remove unneeded BULK_* #defines

We don't need the defines for the number of bulk in or out endpoints
anymore, as the driver just grabs the first ones it finds and runs with
it.

Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>