CANN: Remove unused `ggml_cann_get_device` function (#18625)

ggml/src/ggml-cann/common.h

@@ -101,7 +101,6 @@ struct ggml_cann_device_info {
 const ggml_cann_device_info & ggml_cann_info();
 
 void    ggml_cann_set_device(int32_t device);
-int32_t ggml_cann_get_device();
 
 std::optional<std::string> get_env_as_lowercase(const std::string & name);
 bool                       parse_bool(const std::string & value);

ggml/src/ggml-cann/ggml-cann.cpp

@@ -93,17 +93,6 @@ void ggml_cann_set_device(const int32_t device) {
     g_current_cann_device = device;
 }
 
-/**
- * @brief Retrieves the current device ID.
- *
- * @return The current device ID.
- */
-int32_t ggml_cann_get_device() {
-    int32_t id;
-    ACL_CHECK(aclrtGetDevice(&id));
-    return id;
-}
-
 /**
  * @brief Get the value of the specified environment variable (name) as lowercase.
  *        if not empty, return a std::string object