Don't embed the method table in the AST

Copied from JuliaGPU/CUDA.jl#1112

Author: jpsamaroo

src/device/gcn/helpers.jl

@@ -82,7 +82,7 @@ import ExprTools
 
 macro device_override(ex)
     esc(quote
-        $GPUCompiler.@override($method_table, $ex)
+        $GPUCompiler.@override(AMDGPU.method_table, $ex)
     end)
 end