drm: bridge: it66121: Don't clear DDC FIFO twice

The DDC FIFO was cleared before the loop in it66121_get_edid_block(),
and at the beginning of each iteration; which means that it did not have
to be cleared before the loop.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214125821.12489-8-paul@crapouillou.net