[IA64] make mmu_context.h and tlb.c 80-column friendly

wrap_mmu_context(), delayed_tlb_flush(), get_mmu_context() all
have an extra { } block which cause one extra indentation.
get_mmu_context() is particularly bad with 5 indentations to
the most inner "if".  It finally gets on my nerve that I can't
keep the code within 80 columns.  Remove the extra { } block
and while I'm at it, reformat all the comments to 80-column
friendly.  No functional change at all with this patch.

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