video: Add small 4x6 font from Linux

This font is based on Linux drivers/video/console/font_mini_4x6.c as of commit:

commit bcfbeecea11c15e243f076d37d637c2598aff4fe
Author: Bjarni Ingi Gislason <bjarniig@rhi.hi.is>
Date:   Sun Aug 12 15:05:10 2012 +0000

    drivers: console: font_: Change a glyph from "broken bar" to "vertical line"

I removed these lines as they are useless in U-Boot:
  #include <linux/font.h>
  #define FONTDATAMAX 1536
  Whole "const struct font_desc font_mini_4x6" block

This patch also adds a new configuration option to select this smaller font,
CONFIG_VIDEO_FONT_4X6 , but this is disabled by default. The default setting
is the regular "large" font.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Anatolij Gustschin <agust@denx.de>

include/video_font.h

@@ -8,6 +8,10 @@
 #ifndef _VIDEO_FONT_
 #define _VIDEO_FONT_
 
+#ifdef CONFIG_VIDEO_FONT_4X6
+#include <video_font_4x6.h>
+#else
 #include <video_font_data.h>
+#endif
 
 #endif /* _VIDEO_FONT_ */