arm64: dts: add the Alpine v2 EVP

This patch adds the initial support for the Alpine v2 EVP board from
Annapurna Labs (Amazon).

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Barak Wasserstrom <barak@annapurnalabs.com>
Signed-off-by: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>