m48t59: introduce new base-year qdev property

Currently the m48t59 device uses the hardware model in order to determine
whether the year value is offset from the hardware value. As this will
soon be required by the x59 model, create a qdev base-year property to
represent the base year and update the callers appropriately.

Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
CC: Andreas Färber <afaerber@suse.de>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

include/hw/timer/m48t59.h

@@ -26,8 +26,9 @@ typedef struct NvramClass {
 } NvramClass;
 
 Nvram *m48t59_init_isa(ISABus *bus, uint32_t io_base, uint16_t size,
-                       int type);
+                       int base_year, int type);
 Nvram *m48t59_init(qemu_irq IRQ, hwaddr mem_base,
-                   uint32_t io_base, uint16_t size, int type);
+                   uint32_t io_base, uint16_t size, int base_year,
+                   int type);
 
 #endif /* !NVRAM_H */