scripts/spelling.txt: check for "exeeds"

Increase exeeds spelling error check.

Link: https://lkml.kernel.org/r/20210127060049.915-1-zuoqilin1@163.com


Signed-off-by: zuoqilin <zuoqilin@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>