Remove conditional for caller_locations

Kernel#caller_locations was added in ruby 2, and the required ruby
version is 2.5

The Rails version check will also always be true since the minimum Rails
version is 5.2

lib/sprockets/rails/helper.rb

@@ -89,8 +89,7 @@ def compute_asset_path(path, options = {})
             message << "To bypass the asset pipeline and preserve this behavior,\n"
             message << "use the `skip_pipeline: true` option.\n"
 
-            call_stack = Kernel.respond_to?(:caller_locations) && ::Rails::VERSION::MAJOR >= 5 ? caller_locations : caller
-            ActiveSupport::Deprecation.warn(message, call_stack)
+            ActiveSupport::Deprecation.warn(message, caller_locations)
           end
           super
         end