Drop plymouth theme on ppc64le

Not sure why, but it's the plymouth theme that's breaking update
tests on ppc64le; if it's installed, typing into the VT after
boot doesn't change the screen. Removing the plymouth theme from
the base image fixes the problem.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

server-ppc64le.ks

@@ -0,0 +1,16 @@
+bootloader --location=mbr
+network --bootproto=dhcp
+url --mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=fedora-$releasever&arch=$basearch
+repo --name=updates --mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=updates-released-f$releasever&arch=$basearch
+lang en_US.UTF-8
+keyboard us
+timezone --utc America/New_York
+clearpart --all
+autopart
+rootpw weakpassword
+user --name=test --password=weakpassword --plaintext
+poweroff
+
+%packages
+@^server-product-environment
+%end