Set correct return type for Buffer::translated
Set correct return type for Buffer::translated

Astonishingly, this was caught by nvcc, of all compilers.

/attn @abadams

Former-commit-id: 6b5146569525da3869dbe0fdeece995c04936e47
darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide