fbdev/via: fix spelling mistake "Expandsion" -> "Expansion"

Trivial fix to spelling mistake in MODULE_PARM_DESC text.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>