Add machine qemuarm64. The configure files are derived from linaro.
Update:
* rename genericarmv8 to qemuarm64 for coordination in oe-core
* include qemu.inc then remove common part of config
* disable using autoserial
* move arch-armv8.inc from machine/include/arm64 to machine/include/arm
[YOCTO #6487]
Signed-off-by: Kai Kang <kai.kang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
