Fixing determination of CPU devices
Fixing determination of CPU devices

CL_DEVICE_TYPE is actually a bitset. This fixes issues with pocl.

ddemidov/vexcl,ddemidov/vexcl,kapadia/vexcl,Poulpy21/vexcl,Poulpy21/vexcl,Poulpy21/vexcl,kapadia/vexcl