xtensa: add support for the xtensa processor architecture [2/2]

The Xtensa processor architecture is a configurable, extensible,
and synthesizable 32-bit RISC processor core provided by Tensilica, inc.

This is the second part of the basic architecture port, adding the
'arch/xtensa' directory and a readme file.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/Kconfig

@@ -88,6 +88,11 @@ config X86
 	select DM_SPI
 	select DM_SPI_FLASH
 
+config XTENSA
+	bool "Xtensa architecture"
+	select CREATE_ARCH_SYMLINK
+	select SUPPORT_OF_CONTROL
+
 endchoice
 
 config SYS_ARCH
@@ -161,3 +166,4 @@ source "arch/sandbox/Kconfig"
 source "arch/sh/Kconfig"
 source "arch/sparc/Kconfig"
 source "arch/x86/Kconfig"
+source "arch/xtensa/Kconfig"