drm/msm/dp: fix runtime PM leak on connect failure

drm/msm/dp: fix runtime PM leak on connect failure

Make sure to balance the runtime PM usage counter (and suspend) before
returning on connect failures (e.g. DPCD read failures after a spurious
connect event or if link training fails).

Fixes: 5814b8bf086a ("drm/msm/dp: incorporate pm_runtime framework into DP driver")
Cc: stable@vger.kernel.org      # 6.8
Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/582746/
Link: https://lore.kernel.org/r/20240313164306.23133-3-johan+linaro@kernel.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>