asoc: pcm: modify component extraction

Component for channel map mixer control should be
extracted from pcm runtime instead of kcontrol's private data,
because kcontrol's private data in this case points to channel
map info.

CRs-Fixed: 2420279
Change-Id: Ibaeac4739b73a89d17f16cbacb1b5095d546968b
Signed-off-by: Vignesh Kulothungan <vigneshk@codeaurora.org>