KVM: Replace dest_Lowest_Prio and dest_Fixed with self-defined macros

Change
  dest_Loest_Prio -> IOAPIC_LOWEST_PRIORITY
  dest_Fixed -> IOAPIC_FIXED

the original names are x86 specific, while the ioapic code will be reused
for ia64.

Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --cc drivers/kvm/ioapic.c
Simple merge

diff --cc drivers/kvm/irq.h
Simple merge