fix(rockchip): fix documentation in how build bl31 in AARCH64

Rockchip Aarch64 SoCs expect TF-A's BL31

Change-Id: Ie74be32e2bd24c4de38990791b4a03d2b7695b4d
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
1 file changed