cmd: mtdparts: remove mandatory 'mtdparts=' prefix

All U-Boot users must define the mtdparts environment variable with:
setenv mtdparts mtdparts=...

While this may ease the partition declaration job to be passed to
Linux, this is a pure software limitation and forcing this prefix is a
complete non-sense. Let the user to declare manually the mtdparts
variable without the prefix.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/cmd/mtdparts.c b/cmd/mtdparts.c
index 2e54789..f7ed1a0 100644
--- a/cmd/mtdparts.c
+++ b/cmd/mtdparts.c
@@ -44,7 +44,7 @@
  *
  * 'mtdparts' - partition list
  *
- * mtdparts=mtdparts=<mtd-def>[;<mtd-def>...]
+ * mtdparts=[mtdparts=]<mtd-def>[;<mtd-def>...]
  *
  * <mtd-def>  := <mtd-id>:<part-def>[,<part-def>...]
  * <mtd-id>   := unique device tag used by linux kernel to find mtd device (mtd->name)
@@ -62,11 +62,11 @@
  *
  * 1 NOR Flash, with 1 single writable partition:
  * mtdids=nor0=edb7312-nor
- * mtdparts=mtdparts=edb7312-nor:-
+ * mtdparts=[mtdparts=]edb7312-nor:-
  *
  * 1 NOR Flash with 2 partitions, 1 NAND with one
  * mtdids=nor0=edb7312-nor,nand0=edb7312-nand
- * mtdparts=mtdparts=edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
+ * mtdparts=[mtdparts=]edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  *
  */
 
@@ -1099,9 +1099,6 @@
 		return 0;
 	}
 
-	strcpy(p, "mtdparts=");
-	p += 9;
-
 	list_for_each(dentry, &devices) {
 		dev = list_entry(dentry, struct mtd_device, link);
 
@@ -1572,11 +1569,9 @@
 	if (!p)
 		p = mtdparts;
 
-	if (strncmp(p, "mtdparts=", 9) != 0) {
-		printf("mtdparts variable doesn't start with 'mtdparts='\n");
-		return err;
-	}
-	p += 9;
+	/* Skip the useless prefix, if any */
+	if (strncmp(p, "mtdparts=", 9) == 0)
+		p += 9;
 
 	while (*p != '\0') {
 		err = 1;