drm/bridge: lt9611: Fix PLL being unable to lock

commit 2a9df204 upstream.

This fixes PLL being unable to lock, and is derived from an equivalent
downstream commit.

Available LT9611 documentation does not list this register, neither does
LT9611UXC (which is a different chip).

This commit has been confirmed to fix HDMI output on DragonBoard 845c.

Suggested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221213150304.4189760-1-robert.foss@linaro.org


Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>