arch/x86: drivers/loapic_intr.c: move local APIC initialization

In the general case, the local APIC can't be treated as a normal device
with a single boot-time initialization - on SMP systems, each CPU must
initialize its own. Hence the initialization proper is separated from
the device-driver initialization, and said initialization is called
from the early startup-assembly code when appropriate.

Signed-off-by: Charles E. Youse <charles.youse@intel.com>