drm/radeon/kms: register an i2c adapter name for the dp aux bus

drm/radeon/kms: register an i2c adapter name for the dp aux bus

commit a5193fe50e7f21c26d22c17c8196420fac1a3ca7 upstream.

This causes the connector to not be added since i2c init fails
for the adapter.  Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=31688

Noticed by Ari Savolainen.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: Ari Savolainen <ari.m.savolainen@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>