Currently, all ASoC systems are set to use VPMON for DSP1RX5_SRC,
however, this is required only for internal boost systems.
External boost systems require VBSTMON instead of VPMON to be the
input to DSP1RX5_SRC.
Shared Boost Active acts like Internal boost (requires VPMON).
Shared Boost Passive acts like External boost (requires VBSTMON)
All systems require DSP1RX6_SRC to be set to VBSTMON.
Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>