media: i2c: fix spelling mistakes: "enpoint" -> "endpoint"

There are two spelling mistakes in dev_err messages. Fix these.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>