treewide: fdt: Move fdt_get_config_... to ofnode_conf_read...

The current API is outdated as it requires a devicetree pointer.

Move these functions to use the ofnode API and update this globally. Add
some tests while we are here.

Correct the call in exynos_dsim_config_parse_dt() which is obviously
wrong.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/disk/part_efi.c b/disk/part_efi.c
index fdca91a..0ca7eff 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -23,12 +23,11 @@
 #include <malloc.h>
 #include <memalign.h>
 #include <part_efi.h>
+#include <dm/ofnode.h>
 #include <linux/compiler.h>
 #include <linux/ctype.h>
 #include <u-boot/crc.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 #ifdef CONFIG_HAVE_BLOCK_DEVICE
 
 /* GUID for basic data partitons */
@@ -563,9 +562,8 @@
 	 * from the start of the device) to be specified as a property
 	 * of the device tree '/config' node.
 	 */
-	config_offset = fdtdec_get_config_int(gd->fdt_blob,
-					      "u-boot,efi-partition-entries-offset",
-					      -EINVAL);
+	config_offset = ofnode_conf_read_int(
+		"u-boot,efi-partition-entries-offset", -EINVAL);
 	if (config_offset != -EINVAL) {
 		offset_bytes = PAD_TO_BLOCKSIZE(config_offset, dev_desc);
 		offset_blks = offset_bytes / dev_desc->blksz;