Adjust ARMV8 SGEMM unrolling when using the C fallback kernel_2x2 for IOS

Author: martin-frbg

param.h

@@ -2590,8 +2590,13 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define GEMM_DEFAULT_OFFSET_B 0
 #define GEMM_DEFAULT_ALIGN 0x03fffUL
 
+#if defined(OS_DARWIN) && defined(CROSS)
+#define SGEMM_DEFAULT_UNROLL_M  2
+#define SGEMM_DEFAULT_UNROLL N  2
+#else
 #define SGEMM_DEFAULT_UNROLL_M  4
 #define SGEMM_DEFAULT_UNROLL_N  4
+#endif
 
 #define DGEMM_DEFAULT_UNROLL_M  2
 #define DGEMM_DEFAULT_UNROLL_N  2