nanddump: kill -b Omit bad block

since mtd-utils 1.4.7, the omit bad block method has been removed.
(cf commit d8b8f780ec3c916f3990e9227d6bfbb22bf42ef8)

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed