Some legacy HW context code assumptions don't make sense for this new
submission method, so we will place this stuff in a separate file.

Note for reviewers: I've carefully considered the best name for this file
and this was my best option (other possibilities were intel_lr_context.c
or intel_execlist.c). I am open to a certain bikeshedding on this matter,
anyway.

And some point in time, it would be a good idea to split intel_lrc.c/.h
even further, but for the moment just shove everything together.

v2: Change to intel_lrc.c

v3: Squash together with the header file addition
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>