linprocfs: Add nodes for inotify

[markj]

Summary

As documented in https://man7.org/linux/man-pages/man7/inotify.7.html

These map directly onto sysctls under vfs.inotify of the same name.

[des]

sys/compat/linprocfs/linprocfs.c

2234

shouldn't you check the result and return EINVAL if it's invalid or out of range?

[markj]

Try to validate strtol()'s return value.

[des]

sys/compat/linprocfs/linprocfs.c

2237

endp does not need to be initialized.

2239

You should check that endp > newval, unless you're fine with a zero-length write being interpreted as 0.

[markj]

Handle review feedback.