atmel_lcd: Allow contrast polarity to be either positive or negative

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
diff --git a/include/lcd.h b/include/lcd.h
index cd9d49d..0e098d9 100644
--- a/include/lcd.h
+++ b/include/lcd.h
@@ -167,6 +167,7 @@
 	u_long vl_sync;		/* Horizontal / vertical sync */
 	u_long vl_bpix;		/* Bits per pixel, 0 = 1, 1 = 2, 2 = 4, 3 = 8, 4 = 16 */
 	u_long vl_tft;		/* 0 = passive, 1 = TFT */
+	u_long vl_cont_pol_low;	/* contrast polarity is low */
 
 	/* Horizontal control register. */
 	u_long vl_hsync_len;	/* Length of horizontal sync */