ARM: dts: msm: Enable wcnss node in msm8974 LIQUID

Remove AR6004 node and enable wcnss related nodes in
msm8974 LIQUID so that liquid device could use wcnss
wifi solution.

CRs-Fixed: 641765
Change-Id: I4a622c29089268d4f0f148a8dc3c040ceffca8b4
Signed-off-by: Yuanyuan Liu <yuanliu@codeaurora.org>