Thomas Abraham authored Aug 06, 2018 and Arvind Chauhan committed Oct 11, 2018

The BL config stage is not required for SGI platforms. Add a new
flag to conditionally enable the BL config stage. The platforms
that need the BL config stage will have to enable it.

Change-Id: I188a22de4118bcec19b98103d4909a207c2052ee
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>