[IA64] use fc.i for fluch_icache_range()

This is a small patch to switch fluch_icache_range() to use fc.i
instead of fc.  This would save time on processors which can establish
i-cache coherency without flushing the cache-line out to memory (not
that any current processors do).  On existing processors, fc.i behaves
like fc.  The only caveat is that very old assemblers may not know
about fc.i yet.

Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>