cygserver: Speed up non-debug scenario

cygserver: Speed up non-debug scenario

_log/_vlog were always called so we always had a function call hit even
if we're not debugging.  Expand on the debugging macros so the decision
to call _log/_vlog is done in the caller already.  Also, make a log level
difference between syscall_printf and system_printf.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>