[Fix] Fix ATTENTION registry (#729)

* register ATTENTION registry from the parent ATTENTION registry of MMCV to avoid conflict with other repos

* remove redundant file

mmseg/models/backbones/swin.py

@@ -5,7 +5,6 @@ import torch
 import torch.nn as nn
 import torch.nn.functional as F
 from mmcv.cnn import build_norm_layer, trunc_normal_init
-from mmcv.cnn.bricks.registry import ATTENTION
 from mmcv.cnn.bricks.transformer import FFN, build_dropout
 from mmcv.cnn.utils.weight_init import constant_init
 from mmcv.runner import _load_checkpoint
@@ -15,7 +14,7 @@ from torch.nn.modules.normalization import LayerNorm
 from torch.nn.modules.utils import _pair as to_2tuple
 
 from ...utils import get_root_logger
-from ..builder import BACKBONES
+from ..builder import ATTENTION, BACKBONES
 from ..utils import PatchEmbed, swin_convert
 
 

mmseg/models/builder.py

@@ -1,9 +1,11 @@
 import warnings
 
 from mmcv.cnn import MODELS as MMCV_MODELS
+from mmcv.cnn.bricks.registry import ATTENTION as MMCV_ATTENTION
 from mmcv.utils import Registry
 
 MODELS = Registry('models', parent=MMCV_MODELS)
+ATTENTION = Registry('attention', parent=MMCV_ATTENTION)
 
 BACKBONES = MODELS
 NECKS = MODELS