libstrat: fix compilation without pre-compiled header/without lto

libraries/libstratosphere/include/stratosphere/fs/fs_istorage.hpp

@@ -98,11 +98,13 @@ namespace ams::fs {
 
             virtual Result Write(s64 offset, const void *buffer, size_t size) override {
                 /* TODO: Better result? Is it possible to get a more specific one? */
+                AMS_UNUSED(offset, buffer, size);
                 return fs::ResultUnsupportedOperation();
             }
 
             virtual Result SetSize(s64 size) override {
                 /* TODO: Better result? Is it possible to get a more specific one? */
+                AMS_UNUSED(size);
                 return fs::ResultUnsupportedOperation();
             }
     };