ASoC: add support for SmartPA AW8896 in SDM429w

SmartPA aw8896 is used in SDM429w, and is connected to QUAT mi2s.
Add a dailink for it and only enable the dailink when aw8896
is specified in device tree.

Change-Id: I516cbd76279396f35c7fcc9df0aa4bd752fdbb7b
Signed-off-by: Xiao Li <lixiao@codeaurora.org>
(cherry picked from commit 2602c3673620678821f6d696dfbbce1b91b01df1)
Signed-off-by: Albert I <kras@raphielgang.org>