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The current API is outdated as it requires a devicetree pointer.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/common/autoboot.c b/common/autoboot.c
index 5bb2e19..6251c68 100644
--- a/common/autoboot.c
+++ b/common/autoboot.c
@@ -24,6 +24,7 @@
 #include <u-boot/sha256.h>
 #include <bootcount.h>
 #include <crypt.h>
+#include <dm/ofnode.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -424,12 +425,12 @@
 	ulong addr;
 
 	/* Add an env variable to point to a kernel payload, if available */
-	addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
+	addr = ofnode_conf_read_int("kernel-offset", 0);
 	if (addr)
 		env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
 
 	/* Add an env variable to point to a root disk, if available */
-	addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
+	addr = ofnode_conf_read_int("rootdisk-offset", 0);
 	if (addr)
 		env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
 #endif /* CONFIG_SYS_TEXT_BASE */
@@ -446,8 +447,7 @@
 	bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
 
 	if (IS_ENABLED(CONFIG_OF_CONTROL))
-		bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
-						  bootdelay);
+		bootdelay = ofnode_conf_read_int("bootdelay", bootdelay);
 
 	debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);