gmmlib build QA warnings

[CaptainBloodz]

Git head on gentoo gcc 9.2

• QA Notice: Package triggers severe warnings which indicate that it

•        may exhibit random runtime failures.
  

• /var/tmp/portage/media-libs/gmmlib-9999/work/gmmlib-9999/Source/GmmLib/TranslationTable/GmmPageTableMgr.cpp:415:50: warning: converting to non-pointer type 'long unsigned int' from NULL [-Wconversion-null]
• /var/tmp/portage/media-libs/gmmlib-9999/work/gmmlib-9999/Source/GmmLib/TranslationTable/GmmPageTableMgr.cpp:474:31: warning: NULL used in arithmetic [-Wpointer-arith]

[edwarddavidbaker]

Duplicate of issue #61.

[johnmach]

Fixed in 5647e87