checkpatch: add a fixer for missing newline at eof

Remove the trailing error message from the fixed lines.

Link: https://lkml.kernel.org/r/20201017142546.28988-1-trix@redhat.com


Signed-off-by: Tom Rix <trix@redhat.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>