platform/mellanox: Spelling s/platfom/platform/

Fix a misspelling of the word "platform".

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Shych <michaelsh@nvidia.com>
Link: https://lore.kernel.org/r/9c8edde31e271311b7832d7677fe84aba917da8d.1653376503.git.geert@linux-m68k.org


Signed-off-by: Hans de Goede <hdegoede@redhat.com>