drm/i915: fix a possible refcount leak in intel_dp_add_mst_connector()

stable inclusion
from stable-v5.10.132
commit 592f3bad00b7e2a95a6fb7a4f9e742c061c9c3c1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YS3T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=592f3bad00b7e2a95a6fb7a4f9e742c061c9c3c1



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[ Upstream commit 85144df9 ]

If drm_connector_init fails, intel_connector_free will be called to take
care of proper free. So it is necessary to drop the refcount of port
before intel_connector_free.

Fixes: 091a4f91 ("drm/i915: Handle drm-layer errors in intel_dp_add_mst_connector")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220624130406.17996-1-jose.souza@intel.com


Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
(cherry picked from commit cea9ed61)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>