memblock, x86: Reimplement memblock_find_dma_reserve() using iterators

memblock, x86: Reimplement memblock_find_dma_reserve() using iterators

memblock_find_dma_reserve() wants to find out how much memory is
reserved under MAX_DMA_PFN.  memblock_x86_memory_[free_]in_range() are
used to find out the amounts of all available and free memory in the
area, which are then subtracted to find out the amount of reservation.

memblock_x86_memblock_[free_]in_range() are implemented using
__memblock_x86_memory_in_range() which builds ranges from memblock and
then count them, which is rather unnecessarily complex.

This patch open codes the counting logic directly in
memblock_find_dma_reserve() using memblock iterators and removes now
unused __memblock_x86_memory_in_range() and find_range_array().

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310462166-31469-11-git-send-email-tj@kernel.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>