drm/sun4i: lvds: Invert the LVDS polarity

The LVDS controller can invert the polarity / lanes of the LVDS output.
The default polarity causes some issues on some panels.

However, U-Boot has always used the opposite polarity without any reported
issue, and the only currently supported LVDS panel in-tree (the TBS A711)
seems to be able to work with both settings.

Let's just use the same polarity than U-Boot to be more consistent and
hopefully support all the panels.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Cc: Ondrej Jirman <megous@megous.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200704133803.37330-1-maxime@cerno.tech

drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -474,9 +474,7 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon *tcon,
 		     SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
 		     SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
 
-	reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0 |
-		SUN4I_TCON0_LVDS_IF_DATA_POL_NORMAL |
-		SUN4I_TCON0_LVDS_IF_CLK_POL_NORMAL;
+	reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0;
 	if (sun4i_tcon_get_pixel_depth(encoder) == 24)
 		reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS;
 	else