rusticl: Add clCreateSubDevices stub

unified-runtime tries to call this unconditionally. It handles errors
correctly, but calling None here isn't an error, it's a crash. Just
return CL_INVALID_VALUE so we don't crash.

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30699>

src/gallium/frontends/rusticl/api/device.rs

@@ -372,6 +372,20 @@ fn release_device(_device: cl_device_id) -> CLResult<()> {
     Ok(())
 }
 
+#[cl_entrypoint(clCreateSubDevices)]
+fn create_sub_devices(
+    _device: cl_device_id,
+    _properties: *const cl_device_partition_property,
+    _num_devices: cl_uint,
+    _out_devices: *mut cl_device_id,
+    _num_devices_ret: *mut cl_uint,
+) -> CLResult<()> {
+    // CL_INVALID_VALUE if values specified in properties are not valid or
+    // if values specified in properties are valid but not supported by the
+    // device.
+    Err(CL_INVALID_VALUE)
+}
+
 #[cl_entrypoint(clGetDeviceAndHostTimer)]
 fn get_device_and_host_timer(
     device: cl_device_id,

src/gallium/frontends/rusticl/api/icd.rs

@@ -115,7 +115,7 @@ pub static DISPATCH: cl_icd_dispatch = cl_icd_dispatch {
     clRetainDeviceEXT: None,
     clReleaseDeviceEXT: None,
     clCreateEventFromGLsyncKHR: None,
-    clCreateSubDevices: None,
+    clCreateSubDevices: Some(clCreateSubDevices),
     clRetainDevice: Some(clRetainDevice),
     clReleaseDevice: Some(clReleaseDevice),
     clCreateImage: Some(clCreateImage),