mm/memblock: reduce overhead in binary search

"v1 -> v2":
* move check from memblock_search to memblock_is_memory
* modify changelog

When checking the indicated address belongs to the memory region, the
memory regions are checked one by one through binary search, which would
be a little time consuming. If the indicated address isn't in memory
region, then we needn't do the time-sonsuming search. The patch adds
more check on the indicated address for that purpose.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
[PATCH] mmc: Make sure host is disabled on suspend