soc:msm: Update routing of MSM_FRONTEND_DAI_MULTIMEDIA1

In our snd_soc_msm_2x we have MultiMedia1 Mixer routed to AUX_PCM_TX sink.
Currently the frontend doesnt have support for this in mixer_controls but does allow it(line 1539).

This allows for the DAI Backend to be enabled for MSM8960 Media1.