[ROCm]: Update rope+kvcache fusion conditions and disable custom op by default (#36716)

Signed-off-by: Rohan138 <rohanpotdar138@gmail.com>

docs/design/optimization_levels.md

@@ -56,7 +56,6 @@ Fusions:
 - `-cc.pass_config.fuse_norm_quant=True`*
 - `-cc.pass_config.fuse_act_quant=True`*
 - `-cc.pass_config.fuse_act_padding=True`†
-- `-cc.pass_config.fuse_rope_kvcache=True`† (will be moved to O2)
 
 \* These fusions are only enabled when either op is using a custom kernel, otherwise Inductor fusion is better.</br>
 † These fusions are ROCm-only and require AITER.
@@ -71,6 +70,9 @@ Settings (on top of `-O1`):
 
 - `-cc.cudagraph_mode=FULL_AND_PIECEWISE`
 - `-cc.pass_config.fuse_allreduce_rms=True`
+- `-cc.pass_config.fuse_rope_kvcache=True`†
+
+† These fusions are ROCm-only and require AITER.
 
 ### `-O3`: Aggressive Optimization