fixed compilation error with undefined ARRAY_SIZE

Signed-off-by: Andriy Prystupa <andriy.prystupa@globallogic.com>
[depends] ffmpeg: define make threads if number of cpu cores detection fails

fixes native building on some ARM platforms
Merge pull request #5757 from wsnipex/ffmpeg-arm-build

[depends] ffmpeg: define make threads if number of cpu cores detection f...
Merge pull request #5760 from cisco-open-source/compilation_fix

fixed compilation error with undefined ARRAY_SIZE