falconide: locking bugfix

commit 8ac4ce742c66100931b6f2d7a36b0df08bc721fe ("ide: fix host drivers
depending on ide_generic to probe for interfaces (take 2)") moved probing
to falconide but forgot to take care of Atari specific locking - fix it.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michael Schmitz <schmitz@debian.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>