workaround to make clfft run on NV
NV workaround. Using the command queue to get the device id
Merge pull request #23 from AMD-FirePro/develop

workaround to make clfft run on NV

This adds a vendor check to generate the constant twiddle factors in a global array on an Nvidia runtime stack, bypassing what appears to be a runtime bug generating the table in constant memory.  If the bug disappears from the runtime stack in the future, the vendor check should be removed again.