renderer_vulkan: Bump vertex buffer size

* So software shaders don't crash

src/video_core/renderer_vulkan/vk_rasterizer.cpp

@@ -88,7 +88,7 @@ constexpr VertexLayout RasterizerVulkan::HardwareVertex::GetVertexLayout() {
     return layout;
 }
 
-constexpr u32 VERTEX_BUFFER_SIZE = 64 * 1024 * 1024;
+constexpr u32 VERTEX_BUFFER_SIZE = 128 * 1024 * 1024;
 constexpr u32 INDEX_BUFFER_SIZE = 8 * 1024 * 1024;
 constexpr u32 UNIFORM_BUFFER_SIZE = 16 * 1024 * 1024;
 constexpr u32 TEXTURE_BUFFER_SIZE = 16 * 1024 * 1024;