torchcodec-xpu: delegate CPU fallback to torchcodec CPU device interface

[dvrogozh]

torchlib-xpu/packages/torchcodec-xpu/src/torchcodec_xpu/XpuDeviceInterface.cpp

Lines 372 to 373 in 3baad3c

	// Self-contained SW->RGB conversion via libswscale. We do not delegate to
	// CpuDeviceInterface because its constructor and the createDeviceInterface

We did not delegate the fallback to CPU device interface because torchcodec did not expose createDeviceInterface externally. This got fixed in:

• Expose createDeviceInterface() as a public API meta-pytorch/torchcodec#1346 for main
• [Cherry-pick for 0.12] Expose createDeviceInterface() as a public API (#1346) meta-pytorch/torchcodec#1365 for v0.12.x

Thus, we need to switch fallback to CPU device interface now.

CC: @eromomon

[dvrogozh]

Filed #46