of_device_ids are not supposed to change at runtime. All functions
working with of_device_ids provided by <linux/of.h> work with const
of_device_ids. So mark the non-const structs as const.
File size before:
text data bss dec hex filename
3946 2296 0 6242 1862 drivers/ata/sata_rcar.o
File size after constify sata_rcar_match.
text data bss dec hex filename
5554 696 0 6250 186a drivers/ata/sata_rcar.o