drm/sti: do not remove the drm_bridge that was never added

Removing the drm_bridge_remove call should avoid a NULL dereference
during list processing in drm_bridge_remove if the error path is ever
taken.

The more natural approach would perhaps be to add a drm_bridge_add,
but there are several other bridges that never call drm_bridge_add.
Just removing the drm_bridge_remove is the easier fix.

Fixes: 84601dbd ("drm: sti: rework init sequence")
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180806061910.29914-2-peda@axentia.se