qemu_cpu.cfg: run cpuid.custom test cases with and without KVM

This will help us check if we didn't break anything in KVM-specific or
TCG-specific code inside QEMU.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

qemu/tests/cfg/qemu_cpu.cfg

@@ -122,8 +122,6 @@
                         cpu.amd:
                                 vendor = "AuthenticAMD"
                 - custom:
-                    # run these tests only with kvm disabled:
-                    only nokvm
                     # the checks below will be run without setting the CPU model
                     # explicitly. they can be repeated for each known CPU model
                     # if removing the following line: