The dotclock is three orders of magnitude out. Fix it.

v2: Just set it to 20MHz (Linus)

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200309133644.32385-1-ville.syrjala@linux.intel.comReviewed-by: Linus Walleij <linus.walleij@linaro.org>