drm/meson: Fix OSD1 RGB to YCbCr coefficient

VPP_WRAP_OSD1_MATRIX_COEF22.Coeff22 is documented as being bits 0-12,
not 16-28.

Without this the output tends to have a pink hue, changing it results
in better color accuracy.

The vendor kernel doesn't use this register. However the code which
sets VIU2_OSD1_MATRIX_COEF22 also uses bits 0-12. There is a slightly
different style of registers for configuring some of the other matrices,
which do use bits 16-28 for this coefficient, but those have names
ending in MATRIX_COEF22_30, and this is not one of those.

Signed-off-by: Stuart Menefy <[e-mail]>
Fixes: 728883948b0d ("drm/meson: Add G12A Support for VIU setup")
Reviewed-by: Neil Armstrong <[e-mail]>
Signed-off-by: Neil Armstrong <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/meson/meson_viu.c

···
 		priv->io_base + _REG(VPP_WRAP_OSD1_MATRIX_COEF11_12));
 	writel(((m[9] & 0x1fff) << 16) | (m[10] & 0x1fff),
 		priv->io_base + _REG(VPP_WRAP_OSD1_MATRIX_COEF20_21));
-	writel((m[11] & 0x1fff) << 16,
+	writel((m[11] & 0x1fff),
 		priv->io_base +	_REG(VPP_WRAP_OSD1_MATRIX_COEF22));
 
 	writel(((m[18] & 0xfff) << 16) | (m[19] & 0xfff),