drm/meson: vclk: use the correct G12A frac max value

When calculating the HDMI PLL settings for a DMT mode PHY frequency,
use the correct max fractional PLL value for G12A VPU.

With this fix, we can finally setup the 1024x768-60 mode.

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/20190828132311.23881-1-narmstrong@baylibre.com

drivers/gpu/drm/meson/meson_vclk.c

@@ -638,13 +638,18 @@ static bool meson_hdmi_pll_validate_params(struct meson_drm *priv,
 		if (frac >= HDMI_FRAC_MAX_GXBB)
 			return false;
 	} else if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXM) ||
-		   meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXL) ||
-		   meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A)) {
+		   meson_vpu_is_compatible(priv, VPU_COMPATIBLE_GXL)) {
 		/* Empiric supported min/max dividers */
 		if (m < 106 || m > 247)
 			return false;
 		if (frac >= HDMI_FRAC_MAX_GXL)
 			return false;
+	} else if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A)) {
+		/* Empiric supported min/max dividers */
+		if (m < 106 || m > 247)
+			return false;
+		if (frac >= HDMI_FRAC_MAX_G12A)
+			return false;
 	}
 
 	return true;