Drop export of VEX.L prefix

This was previously needed to distinguish VZEROALL and VZEROUPPER. As
mandatory VEX.L is now handled properly, there is no need to export this
encoding detail any longer.

decode.c

@@ -78,14 +78,14 @@ enum PrefixSet
     PREFIX_REP = FD_FLAG_REP,
     PREFIX_REPNZ = FD_FLAG_REPNZ,
     PREFIX_REX = FD_FLAG_REX,
-    PREFIX_VEXL = FD_FLAG_VEXL,
     PREFIX_OPSZ = 1 << 13,
     PREFIX_ADDRSZ = 1 << 14,
     PREFIX_REXB = 1 << 15,
     PREFIX_REXX = 1 << 16,
     PREFIX_REXR = 1 << 17,
     PREFIX_REXW = 1 << 18,
-    PREFIX_VEX = 1 << 21,
+    PREFIX_VEXL = 1 << 19,
+    PREFIX_VEX = 1 << 20,
 };
 
 typedef enum PrefixSet PrefixSet;