PowerPC64 ragg2 unimplemented

2 failing tests for PPC https://travis-ci.com/github/radareorg/radare2/jobs/440528096#L847

[XX] db/tools/ragg2 ragg2 debruijn sequence 2
R2_NOPLUGINS=1 radare2 -escr.utf8=0 -escr.color=0 -escr.interactive=0 -N -Qc '!ragg2 -P 2 -r; ?e' -
-- stdout
@@ -1 +1 @@
-AA
+
-- stderr
r_egg_assemble: invalid assembly

[XX] db/tools/ragg2 ragg2 debruijn sequence 1
R2_NOPLUGINS=1 radare2 -escr.utf8=0 -escr.color=0 -escr.interactive=0 -N -Qc '!ragg2 -r -P 2; ?e' -
-- stdout
@@ -1 +1 @@
-AA
+
-- stderr
r_egg_assemble: invalid assembly