targets: add TARGET_HAS_BUZZER to c11x, c139 and dsample This new target config preprocessor symbol was introduced in Tourmaline in connection with the new approach to playing buzzer melodies via PWT, properly omitting the responsible code on targets where BU output controls the vibrator instead. That code is not present in Magnetite and we have no plans to backport it here, but target header files should be kept consistent between the two trees, especially given that we plan to support FC Venus target in Magnetite.