Vulkan: fix NaN in tanh.comp with AMD proprietary driver on Windows (ggml-org#10723)

* Vulkan: fix NaN in tanh.comp

* Faster NaN-free tanh

Author: stduhpf

ggml/src/ggml-vulkan/vulkan-shaders/tanh.comp

@@ -16,6 +16,5 @@ void main() {
     if (i >= p.KX) {
         return;
     }
-
-    data_d[i] = D_TYPE(tanh(data_a[i]));
+    data_d[i] = D_TYPE(1. - 2. / (exp(2.*data_a[i]) + 1.));
 }