drm/i915/mst: Fix .mode_valid_ctx() return values

stable inclusion
from stable-v6.6.7
commit 654748c6fc6a403f141d85d71d3d24dd5a2af6fc
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8SSQ4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=654748c6fc6a403f141d85d71d3d24dd5a2af6fc



--------------------------------

commit 7cf82b25dd91d7f330d9df2de868caca14289ba1 upstream.

.mode_valid_ctx() returns an errno, not the mode status. Fix
the code to do the right thing.

Cc: stable@vger.kernel.org
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: d51f25eb ("drm/i915: Add DSC support to MST path")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127145028.4899-2-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit c1799032d2ef6616113b733428dfaa2199a5604b)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>