Renamed various msp3400 routing defines to be more consistent and less
confusing. Esp. the MSP_DSP_OUT defines were confusing since it is really
a DSP input.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>