Simplify minimum ROCm version check

installer.py

@@ -532,7 +532,7 @@ def is_rocm_available():
                 torch_command = os.environ.get('TORCH_COMMAND', 'torch torchvision --index-url https://download.pytorch.org/whl/rocm6.0')
             elif rocm_ver == "6.1": # need nightlies
                 torch_command = os.environ.get('TORCH_COMMAND', 'torch torchvision --pre --index-url https://download.pytorch.org/whl/nightly/rocm6.1')
-            elif int(rocm_ver.rsplit(".")[0]) <= 4 or (int(rocm_ver.rsplit(".")[0]) == 5 and int(rocm_ver.rsplit(".")[1]) <= 5): # oldest supported version is 5.5
+            elif float(rocm_ver) < 5.5: # oldest supported version is 5.5
                 log.warning(f"Unsupported ROCm version detected: {rocm_ver}")
                 log.warning("Minimum supported ROCm version is 5.5")
                 torch_command = os.environ.get('TORCH_COMMAND', 'torch torchvision --index-url https://download.pytorch.org/whl/rocm5.5')