drm/i915/gtt: Introduce fill_page_dma()
drm/i915/gtt: Introduce fill_page_dma()

When we setup page directories and tables, we point the entries
to a to the next level scratch structure. Make this generic
by introducing a fill_page_dma which maps and flushes. We also
need 32 bit variant for legacy gens.

v2: Fix flushes and handle valleyview (Ville)
v3: Now really fix flushes (Michel, Ville)

Reviewed-by: Michel Thierry <c65ff7d3dfaea3345301797f027f123ededb124c@intel.com>
Signed-off-by: Mika Kuoppala <cd221c71e765d1ce593d15b204fee351fb09fd98@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs