gvt-next-2020-05-12

- Support PPGTT update via LRI cmd (Zhenyu)
- Remove extra kmap for shadow ctx update (Zhenyu)
- Move workload cleanup out of execlist handling code (Zhenyu)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
From: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512094017.GX18545@zhen-hp.sh.intel.com