nios2: remove arch specific early_init_dt_alloc_memory_arch

Now that the DT core code handles bootmem arches, we can remove the nios2
specific early_init_dt_alloc_memory_arch function.

Cc: Ley Foon Tan <lftan@altera.com>
Cc: nios2-dev@lists.rocketboards.org
Reviewed-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NRob Herring <robh@kernel.org>

arch/nios2/kernel/prom.c

@@ -42,11 +42,6 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 
 }
 
-void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
-{
-	return alloc_bootmem_align(size, align);
-}
-
 int __init early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size,
 					     bool nomap)
 {