dsp: fix MFC config param payload alignment issue

MFC set param failed in DSP due to payload mismatch
and stereo echo reference doesn't work.
Channel type parameter in MFC config payload is an
array of uint16_t, but it is assumed as an array
of uint8_t while copying from device structure.
Fix this by copying the channel type one by one
instead of using memcpy.

CRs-Fixed: 2197468
Change-Id: I4b6959e8db56743ac98da75ddc3aa8f56964b4ca
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>