accel: replace struct CpusAccel with AccelOpsClass

This will allow us to centralize the registration of
the cpus.c module accelerator operations (in accel/accel-softmmu.c),
and trigger it automatically using object hierarchy lookup from the
new accel_init_interfaces() initialization step, depending just on
which accelerators are available in the code.

Rename all tcg-cpus.c, kvm-cpus.c, etc to tcg-accel-ops.c,
kvm-accel-ops.c, etc, matching the object type names.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210204163931.7358-18-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/accel/kvm/meson.build b/accel/kvm/meson.build
index 7e9dafe..8d219be 100644
--- a/accel/kvm/meson.build
+++ b/accel/kvm/meson.build
@@ -1,7 +1,7 @@
 kvm_ss = ss.source_set()
 kvm_ss.add(files(
   'kvm-all.c',
-  'kvm-cpus.c',
+  'kvm-accel-ops.c',
 ))
 kvm_ss.add(when: 'CONFIG_SEV', if_false: files('sev-stub.c'))