staging: dgap: Remove module param and sysfs var rawreadok

This patch removes the rawreadok module param and sysfs var
previously used to enable flip buffer bypass. Code dealing
with that param was removed previously.

Signed-off-by: Mark Hounschell <markh@compro.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>