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
8908 1096 624 10628 2984 drivers/block/swim3.o
File size after constify swim3_match:
text data bss dec hex filename
9708 296 624 10628 2984 drivers/block/swim3.o