sun4m: set default display type to TCX

Commit 6807874d "sun4m: obey -vga none" changed the sun4m machines so that
they could be started without a framebuffer installed, but as no default
display type was configured the machines would start in headless mode without
an explict -vga option.

Set the default display type for all sun4m machines to TCX so that they will
start with a framebuffer if one is not specifically requested.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

hw/sparc/sun4m.c

@@ -1406,6 +1406,7 @@ static void ss5_class_init(ObjectClass *oc, void *data)
     mc->is_default = 1;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("Fujitsu-MB86904");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss5_type = {
@@ -1424,6 +1425,7 @@ static void ss10_class_init(ObjectClass *oc, void *data)
     mc->max_cpus = 4;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-SuperSparc-II");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss10_type = {
@@ -1442,6 +1444,7 @@ static void ss600mp_class_init(ObjectClass *oc, void *data)
     mc->max_cpus = 4;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-SuperSparc-II");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss600mp_type = {
@@ -1460,6 +1463,7 @@ static void ss20_class_init(ObjectClass *oc, void *data)
     mc->max_cpus = 4;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-SuperSparc-II");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss20_type = {
@@ -1477,6 +1481,7 @@ static void voyager_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_SCSI;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("Fujitsu-MB86904");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo voyager_type = {
@@ -1494,6 +1499,7 @@ static void ss_lx_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_SCSI;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-MicroSparc-I");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss_lx_type = {
@@ -1511,6 +1517,7 @@ static void ss4_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_SCSI;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("Fujitsu-MB86904");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo ss4_type = {
@@ -1528,6 +1535,7 @@ static void scls_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_SCSI;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-MicroSparc-I");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo scls_type = {
@@ -1545,6 +1553,7 @@ static void sbook_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_SCSI;
     mc->default_boot_order = "c";
     mc->default_cpu_type = SPARC_CPU_TYPE_NAME("TI-MicroSparc-I");
+    mc->default_display = "tcx";
 }
 
 static const TypeInfo sbook_type = {