mtd-utils: nandwrite: Comment, style fixups

mtd-utils: nandwrite: Comment, style fixups

Comment on "blockalign" default value is incorrect; it only defaults
to a 1x multiplier of the actual block size. Perhaps this is a relic
of early NAND where all block sizes were 16KB?

Reformatted a multi-line comment.

Changed separete "if" statements to a combined "if-else-if" since they
were logically combinable. Should have no effect on results with minor
effect on efficiency.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>