kompute: add backend registry / device interfaces (#10045)

Get in line with the other backends by supporting the newer
backend/device registry interfaces.

Signed-off-by: Sergio Lopez <slp@redhat.com>

ggml/include/ggml-kompute.h

@@ -11,6 +11,8 @@
 extern "C" {
 #endif
 
+#define GGML_KOMPUTE_MAX_DEVICES 16
+
 struct ggml_vk_device {
     int index;
     int type; // same as VkPhysicalDeviceType
@@ -41,6 +43,8 @@ GGML_API bool ggml_backend_is_kompute(ggml_backend_t backend);
 
 GGML_API ggml_backend_buffer_type_t ggml_backend_kompute_buffer_type(int device);
 
+GGML_API ggml_backend_reg_t ggml_backend_kompute_reg(void);
+
 #ifdef __cplusplus
 }
 #endif