[IA64] More Itanium PAL spec updates

Additional updates to conform with Rev 2.2 of Volume 2 of "Intel
Itanium Architecture Software Developer's Manual" (January 2006).

Add pal_bus_features_s bits 52 & 53 (page 2:347)
Add pal_vm_info_2_s field max_purges (page 2:2:451)
Add PAL_GET_HW_POLICY call (page 2:381)
Add PAL_SET_HW_POLICY call (page 2:439)

Sample output before:
---------------------------------------------------------------------
cobra:~ # cat /proc/pal/cpu0/vm_info
Physical Address Space         : 50 bits
Virtual Address Space          : 61 bits
Protection Key Registers(PKR)  : 16
Implemented bits in PKR.key    : 24
Hash Tag ID                    : 0x2
Size of RR.rid                 : 24
Supported memory attributes    : WB, UC, UCE, WC, NaTPage
---------------------------------------------------------------------

Sample output after:
---------------------------------------------------------------------
cobra:~ # cat /proc/pal/cpu0/vm_info
Physical Address Space         : 50 bits
Virtual Address Space          : 61 bits
Protection Key Registers(PKR)  : 16
Implemented bits in PKR.key    : 24
Hash Tag ID                    : 0x2
Max Purges                     : 1
Size of RR.rid                 : 24
Supported memory attributes    : WB, UC, UCE, WC, NaTPage
---------------------------------------------------------------------

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