vga: make Cirrus ISA device optional

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/default-configs/i386-softmmu.mak b/default-configs/i386-softmmu.mak
index e67ebb3..662348e 100644
--- a/default-configs/i386-softmmu.mak
+++ b/default-configs/i386-softmmu.mak
@@ -1,8 +1,10 @@
 # Default configuration for i386-softmmu
 
 include pci.mak
+CONFIG_VGA=y
 CONFIG_VGA_PCI=y
 CONFIG_VGA_ISA=y
+CONFIG_VGA_CIRRUS=y
 CONFIG_VMWARE_VGA=y
 CONFIG_VMMOUSE=y
 CONFIG_SERIAL=y