bootm: Handle kernel_noload on arm64

The ARM64 has 2 MiB alignment requirement for the kernel. When using
fitImage, this requirement may by violated, the kernel will thus be
executed from unaligned address and fail to boot. Do what booti does
and run booti_setup() for kernel_noload images on arm64 to obtain a
suitable aligned address to which the image shall be relocated.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Bin Chen <bin.chen@linaro.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tom Rini <trini@konsulko.com>