global: Convert simple_strtoul() with decimal to dectoul()

It is a pain to have to specify the value 10 in each call. Add a new
dectoul() function and update the code to use it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/load.c b/cmd/load.c
index ec3eed1..381ed1b 100644
--- a/cmd/load.c
+++ b/cmd/load.c
@@ -70,7 +70,7 @@
 		offset = simple_strtol(argv[1], NULL, 16);
 	}
 	if (argc == 3) {
-		load_baudrate = (int)simple_strtoul(argv[2], NULL, 10);
+		load_baudrate = (int)dectoul(argv[2], NULL);
 
 		/* default to current baudrate */
 		if (load_baudrate == 0)
@@ -264,7 +264,7 @@
 		size = hextoul(argv[2], NULL);
 	}
 	if (argc == 4) {
-		save_baudrate = (int)simple_strtoul(argv[3], NULL, 10);
+		save_baudrate = (int)dectoul(argv[3], NULL);
 
 		/* default to current baudrate */
 		if (save_baudrate == 0)
@@ -446,7 +446,7 @@
 		offset = hextoul(argv[1], NULL);
 	}
 	if (argc == 3) {
-		load_baudrate = (int)simple_strtoul(argv[2], NULL, 10);
+		load_baudrate = (int)dectoul(argv[2], NULL);
 
 		/* default to current baudrate */
 		if (load_baudrate == 0)