badblocks: Limit maximum number of bad blocks

badblocks: Limit maximum number of bad blocks

Currently maximum number of bad blocks is not limited in any way.
However our code can really handle at most INT_MAX/2 bad blocks (for
larger numbers binary search indexes start overflowing). So report
number of bad blocks is just too big instead of plain segfaulting.

It won't be too hard to raise the limit but I don't think there's any
real use for disks with over 1 billion of bad blocks...

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>