x86: Further simplify mp_irq info handling

assign_to_mp_irq() is copying the struct mpc_intsrc members one by
one. That's silly. Use memcpy() and let the compiler figure it out.
Same for the identical function assign_to_mpc_intsrc()

mp_irq_mpc_intsrc_cmp() is comparing the struct members one by one,
but no caller ever checks the different return codes. Use memcmp()
instead.

Remove the extra printk in MP_ioapic_info()

Signed-off-by: Feng Tang <feng.tang@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Alan Cox <alan@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
LKML-Reference: <20101208151857.212f0018@feng-i7>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>