target/ppc: fetch code with translator_ld

Signed-off-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>