Fix QtOpenGL module build with -Werror

Build failed with error
"array subscript is above array bounds [-Werror=array-bounds]"
because GCC optimizes three inline calls and sees A[4][4] != A[16].
According to Thiago this may lead to an undefined behavior after all.

Change-Id: I31ec01377d856890f6072369b3acd1f37e4118ab
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>