'struct usb_device_id' and 'struct us_unusual_dev' are not modified in
these drivers.
Constifying these structures moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers (which is the case for struct us_unusual_dev).
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
25249 4261 896 30406 76c6 drivers/usb/storage/alauda.o
3969 672 360 5001 1389 drivers/usb/storage/cypress_atacb.o
After:
=====
text data bss dec hex filename
25461 4041 896 30398 76be drivers/usb/storage/alauda.o
4225 400 360 4985 1379 drivers/usb/storage/cypress_atacb.o