remove move unused reg_init functions from backends

ggml/src/ggml-cann.cpp

@@ -2083,24 +2083,3 @@ void ggml_backend_cann_get_device_memory(int32_t device, size_t* free,
     ggml_cann_set_device(device);
     ACL_CHECK(aclrtGetMemInfo(ACL_HBM_MEM, free, total));
 }
-
-// backend registry
-/**
- * @brief Initializes a CANN backend based on the provided parameters.
- *
- * This function initializes a CANN backend using the device index and then
- * initializes the backend using `ggml_backend_cann_init`.
- *
- * @param params Parameters for initialization (unused in this implementation).
- * @param user_data User data containing the device index to initialize the
- * backend.
- * @return ggml_backend_t The initialized CANN backend.
- */
-static ggml_backend_t ggml_backend_reg_cann_init(const char* params,
-                                                 void* user_data) {
-    ggml_backend_t cann_backend =
-        ggml_backend_cann_init((int)(intptr_t)user_data);
-    return cann_backend;
-
-    GGML_UNUSED(params);
-}

ggml/src/ggml-kompute.cpp

@@ -2016,8 +2016,3 @@ ggml_backend_t ggml_backend_kompute_init(int device) {
 bool ggml_backend_is_kompute(ggml_backend_t backend) {
     return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_kompute_guid());
 }
-
-static ggml_backend_t ggml_backend_reg_kompute_init(const char * params, void * user_data) {
-    GGML_UNUSED(params);
-    return ggml_backend_kompute_init(intptr_t(user_data));
-}

ggml/src/ggml-sycl.cpp

@@ -5240,10 +5240,3 @@ int ggml_backend_sycl_get_device_count() {
     GGML_SYCL_DEBUG("[SYCL] call ggml_backend_sycl_get_device_count\n");
     return ggml_sycl_info().device_count;
 }
-
-static ggml_backend_t ggml_backend_reg_sycl_init(const char * params, void * user_data) {
-    ggml_backend_t sycl_backend = ggml_backend_sycl_init((int) (intptr_t) user_data);
-    return sycl_backend;
-
-    UNUSED(params);
-}

ggml/src/ggml-vulkan.cpp

@@ -6779,14 +6779,6 @@ void ggml_backend_vk_get_device_memory(int device, size_t * free, size_t * total
     }
 }
 
-// backend registry
-static ggml_backend_t ggml_backend_reg_vk_init(const char * params, void * user_data) {
-    ggml_backend_t vk_backend = ggml_backend_vk_init((int) (intptr_t) user_data);
-    return vk_backend;
-
-    UNUSED(params);
-}
-
 // Extension availability
 static bool ggml_vk_instance_validation_ext_available(const std::vector<vk::ExtensionProperties>& instance_extensions) {
 #ifdef GGML_VULKAN_VALIDATE