const_structs.checkpatch: add bus_type

Since commit d492cc2573a0 ("driver core: device.h: make struct bus_type a
const *"), the driver core can properly handle constant struct bus_type.
Make sure that new usages of the struct already enter the tree as const.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ricardo B. Marliere <[e-mail]>
Suggested-by: Thomas Weißschuh <[e-mail]>
Reviewed-by: Thomas Weißschuh <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>
Cc: Joe Perches <[e-mail]>
Cc: Andy Whitcroft <[e-mail]>
Cc: Dwaipayan Ray <[e-mail]>
Cc: Lukas Bulwahn <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

scripts/const_structs.checkpatch

···
 address_space_operations
 backlight_ops
 block_device_operations
+bus_type
 clk_ops
 comedi_lrange
 component_ops