fix: Diffusers and XPU fixes (#5737)

* fix(README): Add device flags for Intel/XPU

Signed-off-by: Richard Palethorpe <io@richiejp.com>

* fix(diffusers/xpu): Set device to XPU and ignore CUDA request when on Intel

Signed-off-by: Richard Palethorpe <io@richiejp.com>

---------

Signed-off-by: Richard Palethorpe <io@richiejp.com>

backend/python/diffusers/run.sh

@@ -6,4 +6,10 @@ else
     source $backend_dir/../common/libbackend.sh
 fi
 
-startBackend $@
+if [ -d "/opt/intel" ]; then
+    # Assumes we are using the Intel oneAPI container image
+    # https://github.com/intel/intel-extension-for-pytorch/issues/538
+    export XPU=1
+fi
+
+startBackend $@