[media] s5p-tv: mark const init data with __initconst instead of __initdata

As long as there is no other non-const variable marked __initdata in the
same compilation unit it doesn't hurt. If there were one however
compilation would fail with

	error: $variablename causes a section type conflict

because a section containing const variables is marked read only and so
cannot contain non-const variables.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Tomasz Stanislawski <t.stanislaws@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-media@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>