omap_gpmc: Clean up omap_gpmc_attach MemoryRegion conversion

Now that all callers of omap_gpmc_attach pass in a MemoryRegion*,
we can remove the base_update and unmap function pointer arguments,
and the opaque pointer that was passed into these callbacks.

We can also remove the base and size fields from omap_gpmc_cs_file_s
as these are no longer necessary (you don't need the base/size
to unmap a MemoryRegion the way you did to undo a mapping made
with cpu_register_physical_memory()).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/hw/omap.h b/hw/omap.h
index db101c6..47c8629 100644
--- a/hw/omap.h
+++ b/hw/omap.h
@@ -120,9 +120,7 @@
 struct omap_gpmc_s;
 struct omap_gpmc_s *omap_gpmc_init(target_phys_addr_t base, qemu_irq irq);
 void omap_gpmc_reset(struct omap_gpmc_s *s);
-void omap_gpmc_attach(struct omap_gpmc_s *s, int cs, MemoryRegion *iomem,
-                void (*base_upd)(void *opaque, target_phys_addr_t new),
-                void (*unmap)(void *opaque), void *opaque);
+void omap_gpmc_attach(struct omap_gpmc_s *s, int cs, MemoryRegion *iomem);
 
 /*
  * Common IRQ numbers for level 1 interrupt handler