display: add separate config option for bochs-display

This allows modern architectures which don't care about vga
compatibility (risc-v for example) build bochs-display without
including all vga emulation too.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20181005160147.892-2-kraxel@redhat.com

default-configs/pci.mak

@@ -44,5 +44,6 @@ CONFIG_SDHCI=y
 CONFIG_EDU=y
 CONFIG_VGA=y
 CONFIG_VGA_PCI=y
+CONFIG_BOCHS_DISPLAY=y
 CONFIG_IVSHMEM_DEVICE=$(CONFIG_IVSHMEM)
 CONFIG_ROCKER=y

hw/display/Makefile.objs

@@ -14,11 +14,11 @@ common-obj-$(CONFIG_SSD0323) += ssd0323.o
 common-obj-$(CONFIG_XEN) += xenfb.o
 
 common-obj-$(CONFIG_VGA_PCI) += vga-pci.o
-common-obj-$(CONFIG_VGA_PCI) += bochs-display.o
 common-obj-$(CONFIG_VGA_PCI) += edid-region.o
 common-obj-$(CONFIG_VGA_ISA) += vga-isa.o
 common-obj-$(CONFIG_VGA_ISA_MM) += vga-isa-mm.o
 common-obj-$(CONFIG_VMWARE_VGA) += vmware_vga.o
+common-obj-$(CONFIG_BOCHS_DISPLAY) += bochs-display.o
 
 common-obj-$(CONFIG_BLIZZARD) += blizzard.o
 common-obj-$(CONFIG_EXYNOS4) += exynos4210_fimd.o