4805 apic_mode global should be an enum

*** 59,69 ****
   *      1                       0       APIC is enabled in xAPIC mode
   *      1                       1       APIC is enabled in X2APIC mode
   * -----------------------------------------------------------
   */
  int     x2apic_enable = 1;
! int     apic_mode = LOCAL_APIC;         /* Default mode is Local APIC */
  
  /* Uses MMIO (Memory Mapped IO) */
  static apic_reg_ops_t local_apic_regs_ops = {
          local_apic_read,
          local_apic_write,
--- 59,69 ----
   *      1                       0       APIC is enabled in xAPIC mode
   *      1                       1       APIC is enabled in X2APIC mode
   * -----------------------------------------------------------
   */
  int     x2apic_enable = 1;
! apic_mode_t apic_mode = LOCAL_APIC;     /* Default mode is Local APIC */
  
  /* Uses MMIO (Memory Mapped IO) */
  static apic_reg_ops_t local_apic_regs_ops = {
          local_apic_read,
          local_apic_write,