Use HW_NCPU on FreeBSD as well

src/nvthread/nvthread.cpp

@@ -1,4 +1,4 @@
-// This code is in the public domain -- Ignacio Castaño <castano@gmail.com>
+// This code is in the public domain -- Ignacio Castaño <castano@gmail.com>
 
 #include "nvthread.h"
 
@@ -98,7 +98,7 @@ uint nv::processorCount() {
     // set the mib for hw.ncpu
     mib[0] = CTL_HW;
 
-#if NV_OS_OPENBSD
+#if NV_OS_OPENBSD || NV_OS_FREEBSD
     mib[1] = HW_NCPU;
 #else
     mib[1] = HW_AVAILCPU;