media: i2c: ov2659: Switch to SPDX Licensing

Switch to SPDX licensing and drop the redundant GPL text.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>