Fix a typo in the documentation.

Patch by Lars Täuber: firstname taeuber gmx net

Originally committed as revision 19820 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/get_bits.h

@@ -145,7 +145,7 @@ LAST_SKIP_CACHE(name, gb, num)
     will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
 
 LAST_SKIP_BITS(name, gb, num)
-    is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
+    is equivalent to LAST_SKIP_CACHE; SKIP_COUNTER
 
 for examples see get_bits, show_bits, skip_bits, get_vlc
 */