libavcodec/jpeg2000.h: fix comments for JPEG2000 markers

The comments for some of the markers were incorrect.
This patch fixes the comments associated with the markers.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/jpeg2000.h

@@ -40,15 +40,15 @@ enum Jpeg2000Markers {
     JPEG2000_SIZ = 0xff51, // image and tile size
     JPEG2000_COD,          // coding style default
     JPEG2000_COC,          // coding style component
-    JPEG2000_TLM = 0xff55, // packed packet headers, tile-part header
-    JPEG2000_PLM = 0xff57, // tile-part lengths
-    JPEG2000_PLT,          // packet length, main header
+    JPEG2000_TLM = 0xff55, // tile-part length, main header
+    JPEG2000_PLM = 0xff57, // packet length, main header
+    JPEG2000_PLT,          // packet length, tile-part header
     JPEG2000_QCD = 0xff5c, // quantization default
     JPEG2000_QCC,          // quantization component
     JPEG2000_RGN,          // region of interest
     JPEG2000_POC,          // progression order change
-    JPEG2000_PPM,          // packet length, tile-part header
-    JPEG2000_PPT,          // packed packet headers, main header
+    JPEG2000_PPM,          // packed packet headers, main header
+    JPEG2000_PPT,          // packed packet headers, tile-part header
     JPEG2000_CRG = 0xff63, // component registration
     JPEG2000_COM,          // comment
     JPEG2000_SOT = 0xff90, // start of tile-part