DT: net: document Ethernet bindings in one place

This patch is an attempt to gather the Ethernet related bindings in one file,
like it's done in the MMC and some other subsystems. It should save some of
the trouble of documenting several properties over and over in each binding
document, instead only making reference to the main file.

I have used the Embedded Power Architecture(TM) Platform Requirements (ePAPR)
standard as a base for the properties description, also documenting some ad-hoc
properties that have been introduced over time despite having direct analogs in
ePAPR.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
index 9d92d42..5748351 100644
--- a/Documentation/devicetree/bindings/net/stmmac.txt
+++ b/Documentation/devicetree/bindings/net/stmmac.txt
@@ -10,8 +10,7 @@
 - interrupt-names: Should contain the interrupt names "macirq"
   "eth_wake_irq" if this interrupt is supported in the "interrupts"
   property
-- phy-mode: String, operation mode of the PHY interface.
-  Supported values are: "mii", "rmii", "gmii", "rgmii".
+- phy-mode: See ethernet.txt file in the same directory.
 - snps,reset-gpio 	gpio number for phy reset.
 - snps,reset-active-low boolean flag to indicate if phy reset is active low.
 - snps,reset-delays-us  is triplet of delays
@@ -28,12 +27,10 @@
 				ignored if force_thresh_dma_mode is set.
 
 Optional properties:
-- mac-address: 6 bytes, mac address
 - resets: Should contain a phandle to the STMMAC reset signal, if any
 - reset-names: Should contain the reset signal name "stmmaceth", if a
 	reset phandle is given
-- max-frame-size:	Maximum Transfer Unit (IEEE defined MTU), rather
-			than the maximum frame size.
+- max-frame-size: See ethernet.txt file in the same directory
 
 Examples: