Kernel/USB: Add interface descriptor accessor

Author: https://github.com/Quaker762
Commit: ed657e3d2b
Pull-request: https://github.com/SerenityOS/serenity/pull/14134
Reviewed-by: https://github.com/b14ckcat
Reviewed-by: https://github.com/linusg

Kernel/Bus/USB/USBInterface.h

@@ -25,6 +25,8 @@ public:
 
     Vector<USBEndpointDescriptor> const& endpoints() const { return m_endpoint_descriptors; }
 
+    USBInterfaceDescriptor const& descriptor() const { return m_descriptor; }
+
 private:
     USBConfiguration const& m_configuration;              // Configuration that this interface belongs to
     USBInterfaceDescriptor const m_descriptor;            // Descriptor backing this interface