m68k: mac: Reword comment using double "in"

People keep on sending (incorrect) patches to remove the second
occurrence of the word "in".  Reword the comment to stop the inflood.

Suggested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/0229879ee3e2d8828707d291cddbb89ac18a10c2.1666945731.git.geert@linux-m68k.org