ASoC: max98090/91: adding DAPM routing for digital output for max98091

Each route connects two widgets, so in this patch, the widget "AIFOUT2L"
audio interface output left secondary mic and "AIFOUT2R" audio interface
output right secondary mic is connected to "SHDN" and also to "SDIEN".
Route with "SHDN" as source is required because "SHDN" controls the
shutdown and must be ON for codec to operate. Therefore, "AIFOUT2L" and
"AIFOUT2R" must be active when "SHDN" is ON. Route with "SDIEN"
is required as serial interface logic must be enabled, that means
serial port must be enabled, which ensures I2S/TDM clocks and serial data
lines are running. This is also the case with audio interface outputs
"AIFOUTL" and "AIFOUTR" in primary mic.

Signed-off-by: Sharique Mohammad <sharq0406@gmail.com>
Link: https://patch.msgid.link/20251023142044.2247989-1-sharq0406@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>