drm/i915: Prevent out of range pt in gen6_for_each_pde
drm/i915: Prevent out of range pt in gen6_for_each_pde

Found by static analysis tool, this was harmless as the pt was not
used out of scope though.

Introduced by commit 678d96fbb3b5995a2fdff2bca5e1ab4a40b7e968
("drm/i915: Track GEN6 page table usage").

Cc: Mika Kuoppala <cd221c71e765d1ce593d15b204fee351fb09fd98@intel.com>
Signed-off-by: Michel Thierry <c65ff7d3dfaea3345301797f027f123ededb124c@intel.com>
Reviewed-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