ARM: dts: fix L2 address in Hi3620

Fix the address of L2 controler register in hi3620 SoC.
This has been wrong from the point that the file was merged
in v3.14.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Acked-by: Wei Xu <xuwei5@hisilicon.com>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>