x86: tangier: Reserve PCI ECAM in motherboard resources

Per PCI firmware specification the ACPI has to reserve the memory
which is defined as PCI ECAM.

Fixes: 39665beed6f7 ("x86: tangier: Enable ACPI support for Intel Tangier")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/arch-tangier/iomap.h b/arch/x86/include/asm/arch-tangier/iomap.h
new file mode 100644
index 0000000..b0fc03e
--- /dev/null
+++ b/arch/x86/include/asm/arch-tangier/iomap.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Copyright (c) 2019 Intel Corporation */
+
+#ifndef _TANGIER_IOMAP_H
+#define _TANGIER_IOMAP_H
+
+#define MCFG_BASE_ADDRESS	0x3f500000
+#define MCFG_BASE_SIZE		0x00100000
+
+#endif	/* _TANGIER_IOMAP_H */