build: use cpu_family for arch checks

e.g. on 32-bit arm, we may have armv6, armv7l, armv7hf, etc which all
generally have the same layouts.  cpu_family() groups all of these into
just 'arm' that the ABI check table is expecting.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/854>

meson.build

@@ -130,7 +130,7 @@ host_defines = [
   [ 's390', 'HAVE_CPU_S390' ],
 ]
 foreach h : host_defines
-  if h.get(0) == host_machine.cpu()
+  if h.get(0) == host_machine.cpu_family()
     core_conf.set(h.get(1), 1)
   endif
 endforeach