DynASM/x86: Add rdpmc instruction.

Thanks to Cosmin Apreutesei.

dynasm/dasm_x86.lua

@@ -1085,6 +1085,7 @@ local map_op = {
   shrd_3 =	"mriqdw:0FACRmU|mrC/qq:0FADRm|mrC/dd:|mrC/ww:",
 
   rdtsc_0 =	"0F31", -- P1+
+  rdpmc_0 =	"0F33", -- P6+
   cpuid_0 =	"0FA2", -- P1+
 
   -- floating point ops