drm: bridge: it66121: Set DDC preamble only once before reading EDID

commit e6685650 upstream

The DDC preamble and target address only need to be set once before
reading the EDID, even if multiple segments have to be read.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214125821.12489-9-paul@crapouillou.net


[nm@ti.com: Backport from upstream next-20240502]
Signed-off-by: Nishanth Menon <nm@ti.com>