[media] coda/imx-vdoa: platform_driver should not be const

[media] coda/imx-vdoa: platform_driver should not be const

The device driver platform is actually written to during registration,
for setting the owner field, so platform_driver_register() does not
take a const pointer:

drivers/media/platform/coda/imx-vdoa.c: In function 'vdoa_driver_init':
drivers/media/platform/coda/imx-vdoa.c:333:213: error: passing argument 1 of '__platform_driver_register' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
 module_platform_driver(vdoa_driver);
In file included from drivers/media/platform/coda/imx-vdoa.c:22:0:
include/linux/platform_device.h:199:12: note: expected 'struct platform_driver *' but argument is of type 'const struct platform_driver *'
 extern int __platform_driver_register(struct platform_driver *,
            ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/platform/coda/imx-vdoa.c: In function 'vdoa_driver_exit':
drivers/media/platform/coda/imx-vdoa.c:333:626: error: passing argument 1 of 'platform_driver_unregister' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

Remove the modifier again.

Fixes: d2fe28feaebb ("[media] coda/imx-vdoa: constify structs")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>