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/bsd-user/main.c b/bsd-user/main.c
index 6501164..7cc0802 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -909,13 +909,14 @@
 #endif
     }
 
+    cpu_type = parse_cpu_option(cpu_model);
     /* init tcg before creating CPUs and to get qemu_host_page_size */
     {
         AccelClass *ac = ACCEL_GET_CLASS(current_accel());
 
         ac->init_machine(NULL);
+        accel_init_interfaces(ac);
     }
-    cpu_type = parse_cpu_option(cpu_model);
     cpu = cpu_create(cpu_type);
     env = cpu->env_ptr;
 #if defined(TARGET_SPARC) || defined(TARGET_PPC)