Revert "disp: msm: dsi: update args for mipi_dsi_dcs_set_display_brightness"

This reverts commit a54fdd7a which was
added because of upstream android-kernel API change 8a744ca6.
In latest android-kernel revision, the commit 8a744ca6
("ANDROID: drm/dsi: Fix byte order of DCS set/get brightness")
got reverted, which was modifying the upstream API and was making
hard to reconcile it to android-4.19 without breaking APIs for GKI.
Android kernel has rolled back the upstream API change and suggested
to implemnet it in downstream side.
The MIPI brightness byte ordering issue is already been taken care in
current dsi driver using bl_inverted_dbv panel config flag.

Change-Id: Ia8964a08a8e0b8290b1bb10ee583de064550017a
Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>