doc: reformat some long lines in kernel-parameters.txt

Reformat text to (mostly) stay within 80 columns of text.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>