arch/x86/acpi: Change message in acpi_write_dbg2_pci_uart to BIOS_DEBUG

When acpi_write_dbg2_pci_uart is called and no pci uart is available the
function prints "Device not found" as an error. This is not correct.

Change the error level to BIOS_DEBUG so coreboot reports the device is
not available but doesn't flag this as an error.

BUG=N/A
TEST=build

Change-Id: I14567bcfcf5a6ff427e418d15bc2675ae7a28f53
Signed-off-by: Wim Vervoorn <wvervoorn@eltan.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38744
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/arch/x86/acpi.c b/src/arch/x86/acpi.c
index 2f793b4..6dab373 100644
--- a/src/arch/x86/acpi.c
+++ b/src/arch/x86/acpi.c
@@ -946,7 +946,7 @@
 	acpi_addr_t address;
 
 	if (!dev) {
-		printk(BIOS_ERR, "%s: Device not found\n", __func__);
+		printk(BIOS_DEBUG, "%s: Device not found\n", __func__);
 		return current;
 	}
 	if (!dev->enabled) {