mm: update cma policy and debug sysfs

mm: update cma policy and debug sysfs

PD#150194: mm: update cma policy and debug sysfs

1. For movable memory, using CMA first, this can help to avoid
   low memory issue and driver can't allocate pages issue;
2. change /proc/slabinfo sysfs with total size print of each slab;
3. change /proc/pagetypeinfo with toatal pages of each migrate type;
4. add statistics for free pages of each migrate type, and show in
   echo m > /proc/sysrq-trigger.

Change-Id: I2fdab73c2d1278cd025185362a1159e4f683166b
Signed-off-by: Tao Zeng <tao.zeng@amlogic.com>