blackfin: fix build warning for unused variable
blackfin: fix build warning for unused variable

Signed-off-by: Steven Miao <eb4bb6630d9afd913be5ae87090c50ac1ba7a4b2@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs