ia64: Nuke two warnings in mca.c that showed in the simulator configuration.

arch/ia64/kernel/mca.c

@@ -267,6 +267,8 @@ ia64_mca_log_sal_error_record(int sal_info_type)
  */
 #ifndef PLATFORM_MCA_HANDLERS
 
+#ifdef CONFIG_ACPI
+
 static irqreturn_t
 ia64_mca_cpe_int_handler (int cpe_irq, void *arg, struct pt_regs *ptregs)
 {
@@ -281,6 +283,8 @@ ia64_mca_cpe_int_handler (int cpe_irq, void *arg, struct pt_regs *ptregs)
 	return IRQ_HANDLED;
 }
 
+#endif /* CONFIG_ACPI */
+
 static void
 show_min_state (pal_min_state_area_t *minstate)
 {
@@ -967,6 +971,8 @@ ia64_mca_cmc_poll (unsigned long dummy)
  * Outputs
  * 	handled
  */
+#ifdef CONFIG_ACPI
+
 static irqreturn_t
 ia64_mca_cpe_int_caller(int cpe_irq, void *arg, struct pt_regs *ptregs)
 {
@@ -1003,6 +1009,8 @@ ia64_mca_cpe_int_caller(int cpe_irq, void *arg, struct pt_regs *ptregs)
 	return IRQ_HANDLED;
 }
 
+#endif /* CONFIG_ACPI */
+
 /*
  *  ia64_mca_cpe_poll
  *