io: support older linux ioctls

[devsnek]

There are many older linux ioctl numbers from before the _IOC convention. With this change you can use null as a sentinel value to access them, for example: handle.ioctl(IOC_DIR_READ, 0x4600, null, 160) to perform the FBIOGET_VSCREENINFO ioctl.

[jow-]

Can you put this PR description into the commit message itself and amend with your signed off by?

git checkout ioctl
git commit --signoff --amend \
  -m "io: support older linux ioctls" \
  -m "" \
  -m "There are many older linux ioctl numbers from before the _IOC convention." \
  -m "With this change you can use null as a sentinel value to access them, for " \
  -m "example: `handle.ioctl(IOC_DIR_READ, 0x4600, null, 160)` to perform the " \
  -m "`FBIOGET_VSCREENINFO` ioctl."
git push origin ioctl --force