fix CMakeLists.txt for aarch64 targets
fix CMakeLists.txt for aarch64 targets

"Advanced SIMD (aka NEON) is mandatory for AArch64, so no command line
option is needed to instruct the compiler to use NEON."

https://stackoverflow.com/questions/29851128/gcc-arm64-aarch64-unrecognized-command-line-option-mfpu-neon

seeul8er/DroneBridge,seeul8er/DroneBridge,seeul8er/DroneBridge,seeul8er/DroneBridge,seeul8er/DroneBridge