kconfig: Introduce HAVE_ARCH_IOMAP

Introduce a new Kconfig option for architecture codes to control
whether it provides io{read,write}{8,16,32} I/O accessor functions.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/Kconfig b/lib/Kconfig
index ccab426..847e797 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -21,6 +21,12 @@
 	  Enable this option to calculate entries for CRC tables at runtime.
 	  This can be helpful when reducing the size of the build image
 
+config HAVE_ARCH_IOMAP
+	bool
+	help
+	  Enable this option if architecture provides io{read,write}{8,16,32}
+	  I/O accessor functions.
+
 config HAVE_PRIVATE_LIBGCC
 	bool