x86: Use __memblock_alloc_base() in early_reserve_e820()

early_reserve_e820() implements its own ad-hoc early allocator using
memblock_x86_find_in_range_size().  Use __memblock_alloc_base()
instead and remove the unnecessary @startt parameter (it's top-down
allocation anyway).

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310462166-31469-6-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>