arm_sync_icache on aarch64

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

The following program can't be linked on my Pinebbook:

#include <machine/sysarch.h>

int main()
{
	return arm_sync_icache(0, 4096);
}

and I can't find an equivalent of libarm on aarch64.

The kernel side has aarch64_icache_sync_range() and it's not an empty
stub: 

$ nm -S /netbsd  | grep aarch64_icache_sync_range
ffffffc00005f5e0 0000000000000054 T aarch64_icache_sync_range

I need this function for rump stubs to sljit. I think I can use
sysarch(ARM_SYNC_ICACHE) but I'm not sure which approach is better.

-- 
Alex