drm/panel: sitronix-st7703: transition to mipi_dsi wrapped functions

Use functions introduced in commit 966e397e ("drm/mipi-dsi:
Introduce mipi_dsi_*_write_seq_multi()") and commit f79d6d28
("drm/mipi-dsi: wrap more functions for streamline handling") for
sitronix-st7703 based panels.
Signed-off-by: Tejas Vipin <tejasvipin76@gmail.com>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240626045244.48858-1-tejasvipin76@gmail.comSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240626045244.48858-1-tejasvipin76@gmail.com