vt-d: don't treat IOAPIC RTE of dest_SMI type specially.

vt-d: don't treat IOAPIC RTE of dest_SMI type specially.

We also need to create IRTE for it since we enable EIM and clear CFI,
or else, the IOAPIC RTE's interrupt message would be blocked by IR unit.

In io_apic_read_remap_rte(), we now use
"apic_pin_2_ir_idx[apic][ioapic_pin]"
rather than "(remap_rte->index_15 << 15) | remap_rte->index_0_14" to
avoid the "interrupt remapping table out of bound error".

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>