Fix the SYSCALLS.TXT documentation and remove a dead script.

We use the system call constants from the kernel header files now,
so there's no need to check that they've been correctly transcribed

This is a work in progress. I've added TODOs to SYSCALLS.TXT explaining
what's left to do.

(cherry-pick of a51916b58b2d211bcf8ffdbe9cf7faa58e57382f.)

Change-Id: I4484acd946b1f548ac3d95327e58add9f98246ab
2 files changed