drop 'qemu-kvm' package on arm7
The Linux kernel has dropped support for allowing 32-bit Arm systems
to host KVM guests as of the 5.7 kernel, and QEMU dropped it in 5.2
IOW, the qemu-kvm package has been obsolete/useless on armv7 for
years now.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>