Update modeling_phi4mm.py to avoid `TypeError: unsupported operand type(s) for *: 'int' and 'NoneType' `

Ensure 'num_logits_to_keep' has always a valid numeric value before the slice is computed to avoid `TypeError: unsupported operand type(s) for *: 'int' and 'NoneType' `

modeling_phi4mm.py

@@ -2143,6 +2143,9 @@ class Phi4MMForCausalLM(Phi4MMPreTrainedModel, GenerationMixin):
 
         hidden_states = outputs[0]
         # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
+        if num_logits_to_keep is None:
+            num_logits_to_keep = hidden_states.size(1)
+
         logits = self.lm_head(hidden_states[:, -num_logits_to_keep:, :])
 
         loss = None