Small fix to fuzzer makefile.
Small fix to fuzzer makefile.

 * Make clear the device specific fuzzers.
 * Make clear the DSPs being disabled for Kintex7

Signed-off-by: Tim 'mithro' Ansell <f857bf86f3aed4a1021a5247bd2399c65b7ad5cd@google.com>

SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray