linux: Enable kernel config option for raw HID devices

[duckfullstop]

Motivation for this change

Uninterruptable Power Supplies (accessed via things like apcupsd and apctest) such as APC's USB models show up as HID devices, but are not explicitely HID devices (and need to be communicated to in RAW). Annoyingly, this requires a non-standard build flag to be set at kernel build time to get them to work, otherwise apcupsd just sits and complains about an unavailable UPS.

You also get some relevant scrollback in dmesg:

[  890.567023] usb 1-1.1.2: new low-speed USB device number 6 using dwc2
[  890.891728] hid-generic 0003:051D:0002.0002: device has no listeners, quitting

Things done

Set the USB_HIDDEV kernel build flag to yes. More information on this flag: https://cateee.net/lkddb/web-lkddb/USB_HIDDEV.html

I'm 99.9% confident that this won't have any adverse effect on any system; it's purely additive, and just exposes these devices on /dev/usb/hiddevX. The flag was added way back in 2.6.22 (and even earlier). Willing to be proved wrong.

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

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[teto]

it's good practice to compare against other distributions. Is it enabled on debian/ubuntu for instance ?

[duckfullstop]

it's good practice to compare against other distributions. Is it enabled on debian/ubuntu for instance ?

Here it is in Debian: https://salsa.debian.org/kernel-team/linux/blob/master/debian/config/config#L940

And in Ubuntu: https://kernel.ubuntu.com/git/ubuntu/ubuntu-cosmic.git/tree/arch/x86/configs/x86_64_defconfig#n242

And in CentOS: https://git.centos.org/rpms/kernel/blob/c7/f/SOURCES/kernel-3.10.0-x86_64.config#_4672

(It may be worth trawling some of these default configs at some point in the future to see if it would be beneficial enabling / allowing easy enablement of other flags)