acpi: Enable ACPI table generation by default on x86

This should ideally be used by all x86 boards in U-Boot. Enable it by
default. If some boards don't use it, the cost is small.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index a594899..00d1d80 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -270,7 +270,7 @@
 
 config ACPIGEN
 	bool "Support ACPI table generation in driver model"
-	default y if SANDBOX || GENERATE_ACPI_TABLE
+	default y if SANDBOX || (GENERATE_ACPI_TABLE && !QEMU)
 	help
 	  This option enables generation of ACPI tables using driver-model
 	  devices. It adds a new operation struct to each driver, to support