media: seco-cec: fix RC_CORE dependency

All other drivers that need RC_CORE have a dependency rather than using
'select', so we should do the same here to avoid circular dependencies
as well as this warning about missing dependencies:

WARNING: unmet direct dependencies detected for RC_CORE
  Depends on [n]: INPUT [=n]
  Selected by [y]:
  - VIDEO_SECO_RC [=y] && MEDIA_SUPPORT [=y] && CEC_PLATFORM_DRIVERS [=y] && VIDEO_SECO_CEC [=y]

Fixes: daef9576 ("media: seco-cec: add Consumer-IR support")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>