emulation/qemu-x86: Select BOOT_DEVICE_NOT_SPI_FLASH

SPI flash is not emulated on these boards.

Change-Id: If29a87441cb26e53c9814ed10ddcfe14752c3965
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52791
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/emulation/qemu-q35/Kconfig b/src/mainboard/emulation/qemu-q35/Kconfig
index 6f072fe..537841e 100644
--- a/src/mainboard/emulation/qemu-q35/Kconfig
+++ b/src/mainboard/emulation/qemu-q35/Kconfig
@@ -16,6 +16,7 @@
 	select MAINBOARD_HAS_LPC_TPM
 	select MAINBOARD_HAS_CHROMEOS
 	select SOUTHBRIDGE_INTEL_COMMON_ACPI_MADT
+	select BOOT_DEVICE_NOT_SPI_FLASH
 
 config VBOOT
 	select VBOOT_MUST_REQUEST_DISPLAY