Remove PR_TAGGED_ADDR_ENABLE from sys/prctl.h

The value of PR_TAGGED_ADDR_ENABLE was incorrect in the installed
headers and the prctl command macros were missing that are needed
for it to be useful (PR_SET_TAGGED_ADDR_CTRL).  Linux headers have
the definitions since 5.4 so it's widely available, we don't need
to repeat these definitions.  The remaining definitions are from
Linux 5.10.

To build glibc with --enable-memory-tagging, Linux 5.4 headers and
binutils 2.33.1 or newer is needed.

Reviewed-by: DJ Delorie <dj@redhat.com>