Revert "drm/i915: cleanup: drm_modeset_lock_all_ctx() --> DRM_MODESET_LOCK_ALL_BEGIN()"

Revert "drm/i915: cleanup: drm_modeset_lock_all_ctx() --> DRM_MODESET_LOCK_ALL_BEGIN()"

This reverts commit 20d6eabaf442df9aa45d14fac20cc8a05dd7c29d.

This patchset breaks on intel platforms and was previously NACK'd by
Ville.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fernando Ramos <greenfoo@u92.eu>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211002154542.15800-15-sean@poorly.run