[TESTS] arm32 basic-test: Add printf and mem based APIs

Signed-off-by: Anup Patel <anup@brainfault.org>
[TESTS] arm32 basic-test: Add fdt-based linux boot support

fdt-based linux booting is the preferred method in ARM-Linux now. This patch introduces the support (source: uboot)

Signed-off-by: Anup Patel <anup@brainfault.org>