lib/igt_kms: doc for the remaining kmstest_ functions

Plus a bit an overview section explaining the split in the library - a
few people (everyone except me it seems) didn't really understand it.

v2: Fix typo'ed s/kmstest_set_vt_graphics_mode/kmstest_get_pipe_from_crtc_id/
in a doc comment spotted by Imre.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed