NuttX kernel should not use the syscall functions, especially after
enabling CONFIG_SCHED_INSTRUMENTATION_SYSCALL, all system functions
will be traced to backend, which will impact system performance.
Signed-off-by: chao an <anchao@xiaomi.com>
1.Don't include unwind.h when arch specific backtrace is enable
2.Built arch specific backtrace wrapper only when enable
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>