The Amlogic G12A HDMI PLL needs some specific settings to lock with
different fractional values for the 5,4GHz mode.

Handle the 1000/1001 variation fractional case here to avoid having
the PLL in an non lockable state.

Fixes: 202b9808 ("drm/meson: Add G12A Video Clock setup")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190605125320.8708-1-narmstrong@baylibre.com