There are some typos, fix them.

s/regsitration/registration
s/santity/sanity
s/decremeting/decrementing
Signed-off-by: NEthon Paul <ethp@qq.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NRalph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200411071544.16222-1-ethp@qq.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>