drm/msm: Add MSM_INFO_GET_FLAGS

In some cases crosvm needs a way to query the cache flags to communicate
them to the guest kernel for guest userspace mapping.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/504453/
Link: https://lore.kernel.org/r/20220923173307.2429872-1-robdclark@gmail.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>