ARM:dts :apq8074: Fix several audio issues for DB

In the new dragon board release the biases for AMIC5 and AMIC6
are updated. Fix cap to external on biases 1 and 4 to reduce noise on
microphones. Inserted configuration of the regulator for speaker driver.

Change-Id: Id268baf30edb996f93dfa350ef0a4dd32c300561
Signed-off-by: Tanya Finkel <tfinkel@codeaurora.org>