Call @dppy.kernel from @dppy.kernel, @njit, @vectorize

[reazulhoque]

• Analyze the possibility and meaning of being able to call @dppy.kernel decorated functions from other @dppy.kernel, @njit, @vectorize decorated functions.
  • Support for Calling Device Functions from numba.jit functions #205
  • Support for Calling Device Functions from Ufuncs #193
• Analyze SYCL kernel calling another SYCL kernel

[reazulhoque]

For writing device functions we provide decorator @dppy.func. We should be able to call a @dppy.func:

• @dppy.func
• @dppy.kernel
• @vectorize