vulkan: use 4 rows for scalar FA large tile size

Author: jeffbolznv

ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -2537,10 +2537,8 @@ static constexpr uint32_t scalar_flash_attention_num_small_rows = 1;
 static uint32_t get_fa_scalar_num_large_rows(uint32_t hsk, uint32_t hsv) {
     if (hsv >= 192) {
         return 2;
-    } else if ((hsv | hsk) & 8) {
-        return 4;
     } else {
-        return 8;
+        return 4;
     }
 }