video: bmp: Fix compilation errors with CONFIG_BMP_xxBPP enabled

Compiling the 'bmp' command with DM and having one of the following macros
enabled:

CONFIG_BMP_16BPP, CONFIG_BMP_24BPP ONFIG_BMP_32BPP

generates this error:

drivers/video/video_bmp.c: In function ‘video_bmp_display’:
drivers/video/video_bmp.c:315:22: error: ‘lcd_line_length’ undeclared (first use in this function)
    fb -= width * 2 + lcd_line_length;
                          ^

This patch moves to using the correct variable instead and enables the
'bmp' command for DM again.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Anatolij Gustschin <agust@denx.de>

drivers/video/video_bmp.c

@@ -312,7 +312,7 @@ int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,
 				fb_put_word(&fb, &bmap);
 
 			bmap += (padded_width - width) * 2;
-			fb -= width * 2 + lcd_line_length;
+			fb -= width * 2 + priv->line_length;
 		}
 		break;
 #endif /* CONFIG_BMP_16BPP */
@@ -325,7 +325,7 @@ int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,
 				*(fb++) = *(bmap++);
 				*(fb++) = 0;
 			}
-			fb -= lcd_line_length + width * (bpix / 8);
+			fb -= priv->line_length + width * (bpix / 8);
 		}
 		break;
 #endif /* CONFIG_BMP_24BMP */
@@ -338,7 +338,7 @@ int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,
 				*(fb++) = *(bmap++);
 				*(fb++) = *(bmap++);
 			}
-			fb -= lcd_line_length + width * (bpix / 8);
+			fb -= priv->line_length + width * (bpix / 8);
 		}
 		break;
 #endif /* CONFIG_BMP_32BPP */