fix(avx): workaround for missing _mm256_setr_m128i in GCC < 8

Author: xingchensong

ggml.c

@@ -188,7 +188,7 @@ typedef double ggml_float;
 #else
 #if !defined(__riscv)
 #include <immintrin.h>
-#if (defined(__GNUC__) && __GNUC__ >= 9) || defined(__INTEL_COMPILER)
+#if (defined(__GNUC__) && __GNUC__ >= 8) || defined(__INTEL_COMPILER)
 #define MM256_SET_M128I(a, b) _mm256_set_m128i((a), (b))
 #else
 #define MM256_SET_M128I(a, b) _mm256_insertf128_si256(_mm256_castsi128_si256(b), (a), 1)