nouveau/gsp/r535: remove a stray unlock in r535_gsp_rpc_send()

This unlock doesn't belong here and it leads to a double unlock in
the caller, r535_gsp_rpc_push().

Fixes: 176fdcbd ("drm/nouveau/gsp/r535: add support for booting GSP-RM")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Timur Tabi <ttabi@nvidia.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a0293812-c05d-45f0-a535-3f24fe582c02@moroto.mountain

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c

@@ -365,10 +365,8 @@ r535_gsp_rpc_send(struct nvkm_gsp *gsp, void *argv, bool wait, u32 repc)
 	}
 
 	ret = r535_gsp_cmdq_push(gsp, rpc);
-	if (ret) {
-		mutex_unlock(&gsp->cmdq.mutex);
+	if (ret)
 		return ERR_PTR(ret);
-	}
 
 	if (wait) {
 		msg = r535_gsp_msg_recv(gsp, fn, repc);