[IA64] pal cache flush patch

Because PAL spec has changed since 2002, you can goto
http://developer.intel.com/design/itanium/manuals/iiasdmanual.htm

 to
download new SDM, all PAL calls should be invoked with psr.ic=1, and
it's caller's responsibility to handle possible tlb miss.
Ia64_pal_cache_flush was written according to old spec, it is obsolete,
and this patch has ia64_pal_cache_flush conform to new spec.

Signed-off-by Anthony Xu <anthony.xu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>