mm: vmstat: add cma statistics

mm: vmstat: add cma statistics

Since CMA is used more widely, it's worth to have CMA allocation
statistics into vmstat.  With it, we could know how agressively system
uses cma allocation and how often it fails.

Link: https://lkml.kernel.org/r/20210302183346.3707237-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: John Dias <joaodias@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=bbb269206f3c914d4f23e023de4ec020abea6d1b
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Change-Id: Iadf5fef76fe6dfa41177cfccf022ea39ae1cb19e