ide: remove CONFIG_IDE_MAX_HWIFS

The benefits of a user settable CONFIG_IDE_MAX_HWIFS have become pretty 
tiny and are no longer considered worth the trouble of an own option.

Simply always #define MAX_HWIFS to 10.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>