media: platform: exynos4-is: Fix spelling mistake "palne" -> "plane"

There are spelling mistakes in a literal string and a comment. Fix them.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>