added missing torch import (NVIDIA#7913)

Signed-off-by: David Mosallanezhad <dmosallanezh@nvidia.com>

nemo/collections/nlp/modules/common/megatron/adapters/mcore_mixins.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import torch
 import torch.nn.functional as F
 from megatron.core.fusions.fused_bias_dropout import get_bias_dropout_add
 from megatron.core.fusions.fused_bias_gelu import bias_gelu_impl