feat: DeepSeek MoE v1 (#942)

* feat: deepseek v1

DeepSeek is still releasing models on the DeepSeek V1 architecture.

```sh
mlx_lm.convert --hf-path deepseek-ai/DeepSeek-Prover-V1.5-RL --mlx-path DeepSeek-Prover-V1.5-RL-8bit --q-bits 8 -q
mlx_lm.generate --model DeepSeek-Prover-V1.5-RL-8bit --ignore-chat-template --max-tokens 512 --prompt 'import Mathlib
import Aesop

set_option maxHeartbeats 0

open BigOperators Real Nat Topology Rat

/-- The second and fourth terms of a geometric sequence are $2$ and $6$. Which of the following is a possible first term?
Show that it is $\frac{2\sqrt{3}}{3}$.-/
theorem amc12b_2003_p6 (a r : ℝ) (u : ℕ → ℝ) (h₀ : ∀ k, u k = a * r ^ k) (h₁ : u 1 = 2)
  (h₂ : u 3 = 6) : u 0 = 2 / Real.sqrt 3 ∨ u 0 = -(2 / Real.sqrt 3) := by'
```

* nits

* nits

* nits

---------

Co-authored-by: Awni Hannun <awni@apple.com>

llms/mlx_lm/tuner/utils.py

@@ -101,6 +101,7 @@ def linear_to_lora_layers(
         "starcoder2",
         "cohere",
         "minicpm",
+        "deepseek",
     ]:
         keys = set(["self_attn.q_proj", "self_attn.v_proj"])
         if model.model_type == "mixtral":