mm: fix misuse of debug_kmap_atomic

Commit 7ca43e75

 ("mm: use debug_kmap_atomic")
introduced some debug_kmap_atomic() in wrong places.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>