[ARM] Provide SRAM & VIDEORAM regions for VExpress-A9 & VExpress-A15 guest

Both VExpress-A9 & VExpress-A15 have SRAM and VIDEORAM regions which is
required for GUI-based OSes (such as Android) hence this patch adds these
RAM regions to guest template of VExpress-A9 and VExpress-A15 guest.

Signed-off-by: Anup Patel <anup@brainfault.org>