media: i2c: GC05A2: Fix spelling mistake "Horizental" -> "Horizontal"

There is a spelling mistake in a string in the gc05a2_test_pattern_menu
array. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>