media: i2c: max9271: Add MODULE_* macros

Since commit 7f03d9fe ("media: i2c: Kconfig: Make MAX9271
a module") the max9271 library is built as a module but no
MODULE_*() attributes were specified, causing a build error
due to missing license information.

ERROR: modpost: missing MODULE_LICENSE() in drivers/media/i2c/max9271.o

Fix this by adding MODULE attributes to the driver.

Fixes: 7f03d9fe

 ("media: i2c: Kconfig: Make MAX9271 a module")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>