arm: armv8 boot options to enable v8
arm: armv8 boot options to enable v8

Modifies FSConfig.py to enable ARMv8 compatibility.
To boot gem5 with ARMv8:
   Download the v8 kernel, .dtb file, and root FS from: http://gem5.org/Download
   Download the ARMv8 toolchain, and add the bin dir to your path:
       http://www.linaro.org/engineering/engineering-projects/armv8
   Build gem5 for ARM
   Build the v8 bootloader (in gem5/system/arm/aarch64_bootloader)
   Make script in gem5/system/arm/aarch64_bootloader will require v8 toolchain,
   drop the produced boot_emm.arm64 in $(M5_PATH)/binaries/
Run:
   $ build/ARM/gem5.fast configs/example/fs.py --machine-type=VExpress_EMM64 \
     --kernel=/path/to/kernel/vmlinux-linaro-tracking \
     --dtb-filename=/path/to/dtb/rtsm_ve-aemv8a.dtb \
     --disk-image=/path/to/img/linaro-minimal-armv8.img

KuroeKurose/gem5,zlfben/gem5,cancro7/gem5,rjschof/gem5,cancro7/gem5,markoshorro/gem5,HwisooSo/gemV-update,rallylee/gem5,markoshorro/gem5,KuroeKurose/gem5,rallylee/gem5,qizenguf/MLC-STT,qizenguf/MLC-STT,powerjg/gem5-ci-test,TUD-OS/gem5-dtu,SanchayanMaity/gem5,austinharris/gem5-riscv,cancro7/gem5,zlfben/gem5,austinharris/gem5-riscv,zlfben/gem5,Weil0ng/gem5,aclifton/cpeg853-gem5,rjschof/gem5,briancoutinho0905/2dsampling,qizenguf/MLC-STT,kaiyuanl/gem5,kaiyuanl/gem5,rallylee/gem5,Weil0ng/gem5,markoshorro/gem5,aclifton/cpeg853-gem5,SanchayanMaity/gem5,TUD-OS/gem5-dtu,rjschof/gem5,powerjg/gem5-ci-test,rallylee/gem5,aclifton/cpeg853-gem5,rallylee/gem5,SanchayanMaity/gem5,cancro7/gem5,markoshorro/gem5,markoshorro/gem5,briancoutinho0905/2dsampling,gedare/gem5,markoshorro/gem5,powerjg/gem5-ci-test,austinharris/gem5-riscv,briancoutinho0905/2dsampling,HwisooSo/gemV-update,gem5/gem5,SanchayanMaity/gem5,SanchayanMaity/gem5,briancoutinho0905/2dsampling,sobercoder/gem5,kaiyuanl/gem5,Weil0ng/gem5,rjschof/gem5,sobercoder/gem5,SanchayanMaity/gem5,TUD-OS/gem5-dtu,HwisooSo/gemV-update,SanchayanMaity/gem5,gem5/gem5,gem5/gem5,zlfben/gem5,HwisooSo/gemV-update,KuroeKurose/gem5,HwisooSo/gemV-update,austinharris/gem5-riscv,gedare/gem5,KuroeKurose/gem5,qizenguf/MLC-STT,HwisooSo/gemV-update,powerjg/gem5-ci-test,briancoutinho0905/2dsampling,sobercoder/gem5,TUD-OS/gem5-dtu,sobercoder/gem5,rjschof/gem5,aclifton/cpeg853-gem5,aclifton/cpeg853-gem5,austinharris/gem5-riscv,KuroeKurose/gem5,TUD-OS/gem5-dtu,sobercoder/gem5,kaiyuanl/gem5,gedare/gem5,sobercoder/gem5,sobercoder/gem5,cancro7/gem5,gem5/gem5,powerjg/gem5-ci-test,Weil0ng/gem5,aclifton/cpeg853-gem5,briancoutinho0905/2dsampling,austinharris/gem5-riscv,rallylee/gem5,KuroeKurose/gem5,cancro7/gem5,qizenguf/MLC-STT,kaiyuanl/gem5,zlfben/gem5,TUD-OS/gem5-dtu,KuroeKurose/gem5,gedare/gem5,gem5/gem5,qizenguf/MLC-STT,kaiyuanl/gem5,gem5/gem5,aclifton/cpeg853-gem5,HwisooSo/gemV-update,cancro7/gem5,markoshorro/gem5,Weil0ng/gem5,zlfben/gem5,rallylee/gem5,rjschof/gem5,briancoutinho0905/2dsampling,gedare/gem5,kaiyuanl/gem5,rjschof/gem5,Weil0ng/gem5,TUD-OS/gem5-dtu,powerjg/gem5-ci-test,gem5/gem5,Weil0ng/gem5,austinharris/gem5-riscv,powerjg/gem5-ci-test,gedare/gem5,gedare/gem5,zlfben/gem5,qizenguf/MLC-STT