scripts/spelling.txt: increase error-prone spell checking

Increase maping spelling error check.

Link: https://lkml.kernel.org/r/20210121092125.2663-1-tangchunyou@163.com


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