drm/vkms: Switch to dynamic allocation for connector

A specific allocation for the connector is not strictly necessary
at this point, but in order to implement dynamic configuration of
VKMS (configFS), it will be easier to have one allocation per
connector.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250117-b4-vkms-allocated-v4-1-8ec8fd21aaf6@bootlin.com


Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>