MAINTAINERS: Add include/hw/intc/i8259.h to the PC chip section

i8259.c is already listed here, so the corresponding header should
be mentioned in this section, too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

MAINTAINERS

@@ -1781,6 +1781,7 @@ F: include/hw/dma/i8257.h
 F: include/hw/i2c/pm_smbus.h
 F: include/hw/input/i8042.h
 F: include/hw/intc/ioapic*
+F: include/hw/intc/i8259.h
 F: include/hw/isa/i8259_internal.h
 F: include/hw/isa/superio.h
 F: include/hw/timer/hpet.h