arm: mvebu: Select SPL_SKIP_LOWLEVEL_INIT on ARMADA_32BIT

Select SPL_SKIP_LOWLEVEL_INIT on 32bit Armada platforms via Kconfig,
as this was removed from mach/config.h in a2ac2b96 ("Convert
CONFIG_SKIP_LOWLEVEL_INIT et al to Kconfig").

Signed-off-by: Stefan Roese <sr@denx.de>
Fixes: a2ac2b96 ("Convert CONFIG_SKIP_LOWLEVEL_INIT et al to Kconfig")
Cc: Tom Rini <trini@konsulko.com>
Cc: Marek Behún <kabel@kernel.org>
Cc: Pali Rohár <pali@kernel.org>
Tested-by: Pali Rohár <pali@kernel.org>