[vmm] add realview-pb-a8 VMM support
Merge pull request #253 from grissiom/qemu-realview-vmm

[vmm] add realview-pb-a8 VMM support
[bsp/rva8] cleanup drivers/SConscript
[bsp/rva8] make sure $BUILD_ROOT_DIR/output/target/vmm is a folder
[bsp/rva8] add mission header in rtt_api.h
Merge pull request #255 from grissiom/qemu-realview-vmm

Qemu realview vmm