doc/changes.src: document the RDPID instruction

Add RDPID to changes.src.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/doc/changes.src b/doc/changes.src
index 61b6511..04ded0f 100644
--- a/doc/changes.src
+++ b/doc/changes.src
@@ -39,6 +39,8 @@
    compatibility with future versions of NASM.  At this time no pragmas
    are implemented and this is merely a dummy directive.
 
+\b Add the \c{RDPID} instruction.
+
 \S{cl-2.12.02} Version 2.12.02
 
 \b Fix preprocessor errors, especially \c{%error} and \c{%warning},