mtmd: add MiMo v2.5 vision (#22883)

* mimo-v2.5: vision support

* mimo-v2.5: use fused qkv for vision

* mimi-v2.5: fix f16 vision overflow

* mimo-v2.5: comment cleanups

* mimo-v2.5: Flash doesn't have mmproj
more cleanup
remember to use filter_tensors

* mimo-v2.5: fix trailing whitespace