aacraid(4): Fix some mostly trivial buffer overruns

strcpy(3) emits a trailing nul byte, trampling fields after the intended
destination. Instead, use strncpy(3), intentionally leaving these fields
not nul-terminated.

Reported by: Coverity
CIDs: 1031024, 1305463, 1305494, 1305545
Sponsored by: EMC / Isilon Storage Division