[ARM] Add ARM32 Guest dts files for Foundation v8 Host.

Our ARM64 port supports ARM32 guests (i.e. Realview-PB-A8,
VExpress-A9, and VExpress-A15) hence we add the missing DTS
files for Foundation v8 Host which enables us to have
pre-configured ARM32 guest on Foundation v8 Model.

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