svrctl(2) update

svrctl(2) update

- synchronize request type with ioctl by making it unsigned long;
- unbreak VFS requests, as they were being sent to PM;
- use proper ioctl direction flags (and new numbers) for requests;
- remove some needless header inclusions;
- svrctl is in libc, make its message name reflect this;
- keep backward compatibility: svrctl is part of the userland ABI.

Change-Id: I44902e8d0d11b8ebc1ef3bda94d2202481743c9b