drm/i915: Fix 32b overflow check in gen8_ppgtt_alloc_page_directories
drm/i915: Fix 32b overflow check in gen8_ppgtt_alloc_page_directories

The patch 69876bed7e008f5fe01538a2d47c09f2862129d0: "drm/i915/gen8:
page directories rework allocation" added an overflow warning, but the
mask had an extra 0. Use less typo-prone option suggested by Dave
instead, to check for (start + length) >= 0x100000000ULL.

This check will be unnecessary after gen8_alloc_va_range handles more
than 4 PDPs (48b addressing).

v2: Really check for 32b overflow (Ville)

Reported-by: Dan Carpenter <ff341aa343d564f9e53e9dcb6996be8c04859a66@oracle.com>
Cc: Dave Gordon <5149a2b8c2356c5ae3395d41127c879982aacbd4@intel.com>
Cc: Ville Syrjälä <cd6e8d405ca90be3a03d5427c5b24fbd2d68dcc4@linux.intel.com>
Signed-off-by: Michel Thierry <c65ff7d3dfaea3345301797f027f123ededb124c@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

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