usf: Include usf_product.mk for USF PDK.

Bug: 234324473
Test: Compile pass. Verified sensor list & sampling on C10.
      The validation is done both on PDK build and tm-d1-dev build.
Signed-off-by: Rick Chen <rickctchen@google.com>
Change-Id: I371104ceeb39d668dabaf2ba5f705146c60d9bab
1 file changed