[IA64] Update printing of feature set bits

Newer Itanium versions have added additional processor feature set
bits.  This patch prints all the implemented feature set bits.  Some
bit descriptions have not been made public.  For those bits, a generic
"Feature set X bit Y" message is printed.  Bits that are not implemented
will no longer be printed.

Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>