checkpatch: fix spelling errors and remove repeated word

Delete repeated word in scripts/checkpatch.pl:
  "are are" -> "are"

Fix typos:
  "commments" -> "comments"
  "falsly" -> "falsely"

Link: https://lkml.kernel.org/r/20201113152316.62975-1-dwaipayanray1@gmail.com


Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>