The 32bit boot support is full of legacy cruft. While it should be
possible to merge the aarch64 support there, a fresh start looks more
promising.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This commit create a common directory, lib/,
for arm and arm64 common code.

It also create lib32/ and lib64/ for 32bit
and 64bit code respectively.

Signed-off-by: Raphael Poggi <poggi.raph@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>