media: ipu-bridge: Move initialization of node_names.vcm to ipu_bridge_init_swnode_names()

Move initialization of node_names.vcm to ipu_bridge_init_swnode_names()
where it belongs.

And make the initialization of nodes[SWNODE_VCM] unconditional,
ipu_bridge_init_swnode_group() takes care of not registering it
when there is no VCM.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>