mako: display: reduce mipi line clock per LGSI spec

Mako's MIPI line clock is a little bit higher than LGSI's recommendation.  Due
to this higher clock, flickering could happen in some panels.  This patch
reduces the MIPI line clock as LGSI's recommendation.

This also reduces current consumption by ~10mA when the LCD is on.

Signed-off-by: Iliyan Malchev <malchev@google.com>