add the codes to check AMD Instinct GPU number (vllm-project#22367)

Signed-off-by: Zhang Jason <ning.zhang2@amd.com>

Author: zhangnju

examples/others/lmcache/disagg_prefill_lmcache_v1/disagg_example_nixl.sh

@@ -21,8 +21,14 @@ check_hf_token() {
 }
 
 check_num_gpus() {
-    # can you check if the number of GPUs are >=2 via nvidia-smi?
-    num_gpus=$(nvidia-smi --query-gpu=name --format=csv,noheader | wc -l)
+    # can you check if the number of GPUs are >=2 via nvidia-smi/rocm-smi?
+    which rocm-smi > /dev/null 2>&1
+    if [ $? -ne 0 ]; then
+	num_gpus=$(nvidia-smi --query-gpu=name --format=csv,noheader | wc -l)
+    else
+	num_gpus=$(rocm-smi --showid | grep Instinct | wc -l)
+    fi
+
     if [ "$num_gpus" -lt 2 ]; then
         echo "You need at least 2 GPUs to run disaggregated prefill."
         exit 1