Skip freebsd driver test when ppc32/ppc64 targets are not configured.

Otherwise, the clang driver falls back to invoking gcc and the ppc tests
fail.

llvm-svn: 149793

clang/test/Driver/freebsd.c

@@ -1,3 +1,4 @@
+// REQUIRES: ppc32-registered-target,ppc64-registered-target
 // RUN: %clang -no-canonical-prefixes -target powerpc-pc-freebsd8 %s \
 // RUN:   --sysroot=%S/Inputs/basic_freebsd_tree -### 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-PPC %s