fix no build cache (#171)

Author: lijinnn

magi_attention/functional/_flex_flash_attn_jit.py

@@ -314,5 +314,5 @@ def get_ffa_jit_mod(
     return spec.build_and_load()
 
 
-if no_build_cache:
+if not no_build_cache:
     get_ffa_jit_mod = lru_cache(maxsize=None)(get_ffa_jit_mod)