ASoC: Intel: Convert all sst_codecs data definition to c99 style

C99 style struct initialization helps in readability as well as
initialization of variables not specified as NULL. This patch
changes the struct data definitions in skl.c that were not in c99 style.

Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
Signed-off-by: Naveen M <naveen.m@intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>