Add the Enhanced Virtual Addressing (EVA) feature to the P5600 core
configuration, along with the related Segmentation Control (SC) feature
and writable CP0_EBase.WG bit.

This allows it to run Malta EVA kernels.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Reviewed-by: NYongbok Kim <yongbok.kim@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NYongbok Kim <yongbok.kim@imgtec.com>