asoc: codec: avoid out of bound write to map array

added check for port num and channel iteration are lessthan 8
to avoid out of bound write to 8x8 map array.

Change-Id: I8d1df91133d5124e90f46ca491f13ac70258f0cc
Signed-off-by: Jing Wang <quic_jingwa@quicinc.com>