ARM: uniphier: add PXs3 SoC support

Initial support for PXs3 SoC.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/doc/README.uniphier b/doc/README.uniphier
index a42eaa9..539b1f2 100644
--- a/doc/README.uniphier
+++ b/doc/README.uniphier
@@ -62,6 +62,10 @@
     $ make uniphier_ld20_defconfig
     $ make CROSS_COMPILE=aarch64-linux-gnu-
 
+PXs3 reference board:
+    $ make uniphier_v8_defconfig
+    $ make CROSS_COMPILE=aarch64-linux-gnu- DEVICE_TREE=uniphier-pxs3-ref
+
 You may wish to change the "CROSS_COMPILE=..." to use your favorite compiler.