UPSTREAM: drm/i915: Shuffle DP .mode_valid() checks

Move some of the more trivial checks in the DP .mode_valid()
hooks upwards to lessen the noise amongst the more complex
checks.

Reviewed-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240402135148.23011-3-ville.syrjala@linux.intel.com


(cherry picked from commit e9fa99dd)

BUG=b:308455498
TEST=Verify Asus PG32UQXR 4K160 mode on Rex using Big Joiner

Change-Id: I11c5b921df4b152bae1044a92bcf2950ff5f630a
Signed-off-by: Rakshith M O <rakshith.m.o@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5802853


Reviewed-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Hubert Mazur <hmazur@google.com>