ACPICA: Fixed possible corruption of global GPE list

Fixed a problem in acpi_ev_delete_gpe_xrupt where the global interrupt
list could be corrupted if the interrupt being removed was at
the head of the list. Reported by Linn Crosetto.
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/events/evgpeblk.c

@@ -586,6 +586,10 @@ acpi_ev_delete_gpe_xrupt(struct acpi_gpe_xrupt_info *gpe_xrupt)
 	flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 	if (gpe_xrupt->previous) {
 		gpe_xrupt->previous->next = gpe_xrupt->next;
+	} else {
+		/* No previous, update list head */
+
+		acpi_gbl_gpe_xrupt_list_head = gpe_xrupt->next;
 	}
 
 	if (gpe_xrupt->next) {