asoc: wcd937x: add dummy widgets to codec input and outputs

With multicodec approach, codec widgets are added much earlier during sound
card registration than aux codec approach. The connections between bolero and wcd938x
are done via device tree at a later point. DAPM does power checkup for codec widgets
before the codec-codec path is connected. This results in wcd937x dapm inputs/output
to be considered as endpoints, which results in playback/record failure once after
bootup. Hence, add dummy output/input widgets to wcd937x dapm inputs/output which are not
codec endpoints.

Change-Id: I8589f9a33261531eaad74e8f12ef1825fa90a014
Signed-off-by: Vangala, Amarnath <avangala@codeaurora.org>