hw/ppc/meson: Allow e500 boards to be enabled separately

Gives users more fine-grained control over what should be compiled into
QEMU.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20221003203142.24355-2-shentey@gmail.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

configs/devices/ppc-softmmu/default.mak

@@ -1,7 +1,8 @@
 # Default configuration for ppc-softmmu
 
 # For embedded PPCs:
-CONFIG_E500=y
+CONFIG_E500PLAT=y
+CONFIG_MPC8544DS=y
 CONFIG_PPC405=y
 CONFIG_PPC440=y
 CONFIG_VIRTEX=y

hw/ppc/Kconfig

@@ -132,6 +132,14 @@ config E500
     select FDT_PPC
     select DS1338
 
+config E500PLAT
+    bool
+    select E500
+
+config MPC8544DS
+    bool
+    select E500
+
 config VIRTEX
     bool
     select PPC4XX

hw/ppc/meson.build

@@ -71,12 +71,10 @@ ppc_ss.add(when: 'CONFIG_MAC_OLDWORLD', if_true: files('mac_oldworld.c'))
 # NewWorld PowerMac
 ppc_ss.add(when: 'CONFIG_MAC_NEWWORLD', if_true: files('mac_newworld.c'))
 # e500
+ppc_ss.add(when: 'CONFIG_E500PLAT', if_true: files('e500plat.c'))
+ppc_ss.add(when: 'CONFIG_MPC8544DS', if_true: files('mpc8544ds.c'))
 ppc_ss.add(when: 'CONFIG_E500', if_true: files(
   'e500.c',
-  'mpc8544ds.c',
-  'e500plat.c'
-))
-ppc_ss.add(when: 'CONFIG_E500', if_true: files(
   'mpc8544_guts.c',
   'ppce500_spin.c'
 ))