Since commit 
30486322 (nand erase: .spread, .part, .chip subcommands)
the arguments off and size are no longer optional.
Signed-off-by: Daniel Hobi <daniel.hobi@schmid-telecom.ch>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
        "    write 'size' bytes starting at offset 'off' with yaffs format\n"
        "    from memory address 'addr', skipping bad blocks.\n"
 #endif
-       "nand erase[.spread] [clean] [off [size]] - erase 'size' bytes "
+       "nand erase[.spread] [clean] off size - erase 'size' bytes "
        "from offset 'off'\n"
        "    With '.spread', erase enough for given file size, otherwise,\n"
        "    'size' includes skipped bad blocks.\n"