[DLight] Update Adreno GEMV Rules (#17016)

When reduction axis is small, it's not necessary to use rfactor. This
PR updates the gemv rule to use rfactor only when the reduction axis is
large enough.

Author: Siyuan Feng

python/tvm/dlight/gpu/gemv.py

@@ -711,7 +711,7 @@ def apply(
         if LOAD_V_SHARED is False:
             LOAD_V_TILE = 1
 
-        if not isinstance(len_r, int):
+        if not isinstance(len_r, int) or len_r < LOAD_V_TILE * TR * SCALE_PACK * DEC_PACK:
             return None
 
         if not isinstance(len_s, int):