ide-h8300: remove custom tf_{read|load}() methods

Since tf_{read|load}() methods of this driver have now become identical to their
standard counterparts using I/O port accesses, there's no need to override those
anymore...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>