r600: fork and import gallium/radeon

This marks the end of code sharing between r600 and radeonsi.
It's getting difficult to work on radeonsi without breaking r600.

A lot of functions had to be renamed to prevent linker conflicts.
There are also minor cleanups.

Acked-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
66 files changed