math/openblas: fix build on powerpc64*

gemv.c:229:31: error: 'GEMM_MULTITHREAD_THRESHOLD' undeclared (first use in this function)
  229 |   if ( 1L * m * n < 115200L * GEMM_MULTITHREAD_THRESHOLD )

math/openblas/files/patch-param.h

+--- param.h.orig	2024-06-23 08:32:52 UTC
++++ param.h
+@@ -2553,7 +2553,7 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILI
+ 
+ #endif
+ 
+-#if defined(POWER9) && defined(OS_LINUX)
++#if defined(POWER9) && (defined(OS_LINUX) || defined(OS_FREEBSD))
+ 
+ #define SNUMOPT		16
+ #define DNUMOPT		8