blackfin: 2012R1 toolchain is gone, remove kludges

Remove ADI toolchain 2012R1 package kludges since that version is gone
since the last bump.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>