drivers/base/memory.c: clean up section counting

Right now, section_count is calculated in add_memory_block().  However,
init_memory_block() increments section_count as well, which, at first,
seems like it would lead to an off-by-one error.  There is no harm done
because add_memory_block() immediately overwrites the
mem->section_count, but it is messy.

This commit moves the increment out of the common init_memory_block()
(called by both add_memory_block() and register_new_memory()) and adds
it to register_new_memory().

Signed-off-by: Seth Jennings <sjennings@variantweb.net>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Greg KH <greg@kroah.com>
Cc: Russ Anderson <rja@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>