IOCTL mapping layer Part I/II

IOCTL mapping layer Part I/II

This adds a generic framework for mapping IOCTL requests (cmds) and
attaching special processing functions. Instead of the former adhoc
code using large switch statements e.g. in emulation/linux/linux_ioctl.c,
the emulation layer registers a handler with the mappings for the request
ranges it wants to handle specially. Devices can afterwards add there
own mappings to support e.g. Linux specific IOCTLs.

The first part adds the infrastructure, the second part converts the Linux
emulation, dev/drm and dev/raid/aac.

Submitted-by: Simon 'corecode' Schubert <corecode@fs.ei.tum.de>
Some minor changes by myself.