vfio/spapr: Only compile sPAPR IOMMU support when needed

sPAPR IOMMU support is only needed for pseries machines. Compile out
support when CONFIG_PSERIES is not set. This saves ~7K of text.

Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index e5d98b6..bb98493 100644
--- a/hw/vfio/meson.build
+++ b/hw/vfio/meson.build
@@ -4,9 +4,9 @@
   'common.c',
   'container-base.c',
   'container.c',
-  'spapr.c',
   'migration.c',
 ))
+vfio_ss.add(when: 'CONFIG_PSERIES', if_true: files('spapr.c'))
 vfio_ss.add(when: 'CONFIG_IOMMUFD', if_true: files(
   'iommufd.c',
 ))