[202012][sonic-platform-common] submodule update

6f198d0 (HEAD -> 202012, origin/202012) [Y-Cable][Broadcom] upgrade to support Broadcom Y-Cable API to release (sonic-net#230)
1c3e422 SSD Health: Retrieve SSD health and temperature values from generic SSD info (sonic-net#229)

Signed-off-by: vaibhav-dahiya <[email protected]>

Author: vdahiya12