With top-down memblock allocation, the allocation range limits in
ealry_node_mem() can be simplified - try node-local first, then any
node but in any case don't allocate below DMA limit.
Remove early_node_mem() and implement simplified allocation directly
in setup_node_bootmem().
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com>