If an error is encountered during the DSI initialization setup, the
drm connector object also needs to be cleaned up along with the encoder.
The error can happen due to a missing mode in the VBT or for other
reasons.

v2: Rephrase the commit message to make it more clear.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200522202630.7604-1-vivek.kasireddy@intel.com