MLK-21045 iMX8QM: Need to change u-boot HDMI TX clocks

MLK-21045 iMX8QM: Need to change u-boot HDMI TX clocks

The HDMI digital PLL, bus clock and core clock need to change to improve the
firmware loading time. The clock are now set to 800 MHz for DPLL, 200 MHz for
HDMI core, and 100 MHz for HDMI bus.

Signed-off-by: Oliver Brown <oliver.brown@nxp.com>
(cherry picked from commit 1d368140f32cce8fc35962b18da6332d383bb094)