Add machine qemuarm64

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]

(From OE-Core rev: d7314c3bc804b7bcc921b0a6c5b63d71ca2e73db)

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/conf/machine/include/arm/arch-armv8.inc

@@ -0,0 +1,20 @@
+DEFAULTTUNE ?= "aarch64"
+
+ARMPKGARCH ?= "aarch64"
+
+TUNEVALID[aarch64] = "Enable instructions for aarch64"
+TUNEVALID[bigendian] = "Enable big-endian mode."
+TUNECONFLICTS[aarch64] = ""
+MACHINEOVERRIDES .= "${@bb.utils.contains("TUNE_FEATURES", "aarch64", ":aarch64", "" ,d)}"
+
+# Little Endian base configs
+AVAILTUNES += "aarch64 aarch64_be"
+TUNE_FEATURES_tune-aarch64 ?= "aarch64"
+TUNE_FEATURES_tune-aarch64_be ?= "${TUNE_FEATURES_tune-aarch64} bigendian"
+
+ARMPKGSFX_ENDIAN = "${@bb.utils.contains("TUNE_FEATURES", "bigendian", "_be", "", d)}"
+
+TUNE_ARCH = "aarch64${ARMPKGSFX_ENDIAN}"
+TUNE_PKGARCH = "aarch64${ARMPKGSFX_ENDIAN}"
+
+PACKAGE_EXTRA_ARCHS = "aarch64${ARMPKGSFX_ENDIAN}"

meta/conf/machine/qemuarm64.conf

@@ -0,0 +1,12 @@
+#@TYPE: Machine
+#@NAME: generic armv8 machine
+#@DESCRIPTION: Machine configuration for running a generic armv8
+
+require conf/machine/include/arm/arch-armv8.inc
+require conf/machine/include/qemu.inc
+
+MACHINE_FEATURES = ""
+
+KERNEL_IMAGETYPE = "Image"
+
+SERIAL_CONSOLE = "38400 ttyAMA0"