tools: mtd-utils: Update to version 2.1.2

The release notes says this:
As already said, the changes since 2.1.1 are primarily bug fixes, addressing
compiler warnings and issues reported by diagnostic tools, but also build
failures for some configurations.
https://lists.infradead.org/pipermail/linux-mtd/2020-July/081299.html

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

tools/mtd-utils/patches/100-sscanf_fix.patch

@@ -1,6 +1,6 @@
 --- a/jffsX-utils/mkfs.jffs2.c
 +++ b/jffsX-utils/mkfs.jffs2.c
-@@ -427,7 +427,7 @@ static int interpret_table_entry(struct
+@@ -428,7 +428,7 @@ static int interpret_table_entry(struct
  
  	if (sscanf (line, "%" SCANF_PREFIX "s %c %lo %lu %lu %lu %lu %lu %lu %lu",
  				SCANF_STRING(name), &type, &mode, &uid, &gid, &major, &minor,