[IA64] lazy_mmu_prot_update needs to be aware of huge pages

Function lazy_mmu_prot_update is also used on huge pages when it is called
by set_huge_ptep_writable, but it isn't aware of huge pages.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Acked-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>