py : use cpu-only torch in requirements.txt (#8335)

examples/llava/requirements.txt

@@ -1,3 +1,4 @@
 -r ../../requirements/requirements-convert_legacy_llama.txt
+--extra-index-url https://download.pytorch.org/whl/cpu
 pillow~=10.2.0
 torch~=2.2.1

requirements/requirements-convert_hf_to_gguf.txt

@@ -1,2 +1,3 @@
 -r ./requirements-convert_legacy_llama.txt
+--extra-index-url https://download.pytorch.org/whl/cpu
 torch~=2.2.1

requirements/requirements-convert_hf_to_gguf_update.txt

@@ -1,2 +1,3 @@
 -r ./requirements-convert_legacy_llama.txt
+--extra-index-url https://download.pytorch.org/whl/cpu
 torch~=2.2.1