LibGL+LibSoftGPU: Add method to query device info

This adds a method `info()` to SoftGPU that returns the name of the
hardware vendor and device name, as well as the number of texture untis.

LibGL uses the returned texture unit count to initialize its internal
texture unit array.

Userland/Libraries/LibSoftGPU/Device.cpp

@@ -498,6 +498,15 @@ Device::Device(const Gfx::IntSize& min_size)
     m_options.scissor_box = m_render_target->rect();
 }
 
+DeviceInfo Device::info() const
+{
+    return {
+        .vendor_name = "SerenityOS",
+        .device_name = "SoftGPU",
+        .num_texture_units = num_samplers
+    };
+}
+
 void Device::draw_primitives(PrimitiveType primitive_type, FloatMatrix4x4 const& transform, FloatMatrix4x4 const& texture_matrix, Vector<Vertex> const& vertices, Vector<size_t> const& enabled_texture_units)
 {
     // At this point, the user has effectively specified that they are done with defining the geometry
@@ -810,8 +819,6 @@ NonnullRefPtr<Image> Device::create_image(ImageFormat format, unsigned width, un
 
 void Device::set_sampler_config(unsigned sampler, SamplerConfig const& config)
 {
-    VERIFY(sampler < num_samplers);
-
     m_samplers[sampler].set_config(config);
 }