armv7: ls102xa: Add workaround for DDR erratum A-008850

Barrier transactions from CCI400 need to be disabled till
the DDR is configured, otherwise it may lead to system hang.
The patch adds workaround to fix the erratum.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@nxp.com>
Signed-off-by: Alison Wang <alison.wang@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>