Merge pull request #1130 from jeenu-arm/gic-patches

New GIC APIs and specifying interrupt propertes

diff --cc docs/firmware-design.rst
Simple merge

diff --cc docs/porting-guide.rst
Simple merge

diff --cc docs/user-guide.rst
Simple merge

diff --cc include/lib/aarch32/arch.h
Simple merge

diff --cc include/lib/aarch64/arch.h
Simple merge

diff --cc include/lib/aarch64/arch_helpers.h
Simple merge