asoc: wcd937x: fix wcd9375 widgets override issue

wcd9375 widgets addition override wcd9370 widgets
registered already in dapm. Need to call
snd_soc_dapm_sync only after adding new widgets/routes.

Change-Id: I285d2f971ca2daae865156e050904fdcc9ea8c3c
signed-off-by: Ramprasad Katkam <katkam@codeaurora.org>