drm/msm/dpu1: Don't set allow_fb_modifiers explicitly

Since

commit 890880dd
Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Date:   Fri Jan 4 09:56:10 2019 +0100

    drm: Auto-set allow_fb_modifiers when given modifiers at plane init

this is done automatically as part of plane init, if drivers set the
modifier list correctly. Which is the case here.

v2: Rebase.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rob Clark <robdclark@chromium.org>
Cc: Kalyan Thota <kalyant@codeaurora.org>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Eric Anholt <eric@anholt.net>
Cc: Tanmay Shah <tanmay@codeaurora.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
Cc: Qinglang Miao <miaoqinglang@huawei.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210427092018.832258-4-daniel.vetter@ffwll.ch