Move xGA font data from lavc to lavu.

This needs to be accessible for libavfilter in the next commit.

libavcodec/cga_data.h

@@ -21,6 +21,7 @@
 /**
  * @file
  * CGA/EGA/VGA ROM data
+ * @note fonts are in libavutil/xga_font_data.[ch]
  */
 
 #ifndef AVCODEC_CGA_DATA_H
@@ -28,8 +29,6 @@
 
 #include <stdint.h>
 
-extern const uint8_t ff_cga_font[2048];
-extern const uint8_t ff_vga16_font[4096];
 extern const uint32_t ff_cga_palette[16];
 extern const uint32_t ff_ega_palette[64];