acpi: Kconfig symbol CONFIG_QFW_ACPI

We have two implementations of write_acpi_tables(). One for writing ACPI
tables based on ACPI_WRITER() entries another based on copying tables from
QEMU.

Create a symbol CONFIG_QFW_ACPI that signifies copying ACPI tables from
QEMU and use it consistently.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/acpi/Makefile b/lib/acpi/Makefile
index c1c9675..cc28684 100644
--- a/lib/acpi/Makefile
+++ b/lib/acpi/Makefile
@@ -12,7 +12,7 @@
 obj-y += acpi_writer.o
 
 # With QEMU the ACPI tables come from there, not from U-Boot
-ifndef CONFIG_QEMU
+ifndef CONFIG_QFW_ACPI
 obj-y += base.o
 obj-y += csrt.o
 obj-y += mcfg.o
diff --git a/lib/acpi/acpi_writer.c b/lib/acpi/acpi_writer.c
index a8dc207..bbb9b54 100644
--- a/lib/acpi/acpi_writer.c
+++ b/lib/acpi/acpi_writer.c
@@ -48,7 +48,7 @@
 	return 0;
 }
 
-#ifndef CONFIG_QEMU
+#ifndef CONFIG_QFW_ACPI
 static int acpi_write_all(struct acpi_ctx *ctx)
 {
 	const struct acpi_writer *writer =
@@ -115,7 +115,7 @@
 
 	return map_to_sysmem(gd->acpi_ctx->rsdp);
 }
-#endif /* QEMU */
+#endif /* QFW_ACPI */
 
 void acpi_setup_ctx(struct acpi_ctx *ctx, ulong start)
 {