Documentation: arm: add Marvell Armada 1500 Mini Plus to SoC list

Add known information about the Marvell BG2CDP SoC that's used in
the Google Chromecast 2015 and Kinoma HD devices.
Signed-off-by: NThomas Hebb <tommyhebb@gmail.com>
Acked-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/arm/Marvell/README

@@ -237,10 +237,14 @@ Berlin family (Multimedia Solutions)
 -------------------------------------
 
   Flavors:
-	88DE3005, Armada 1500-mini
+	88DE3005, Armada 1500 Mini
 		Design name:	BG2CD
 		Core:		ARM Cortex-A9, PL310 L2CC
 		Homepage:	http://www.marvell.com/multimedia-solutions/armada-1500-mini/
+        88DE3006, Armada 1500 Mini Plus
+                Design name:    BG2CDP
+                Core:           Dual Core ARM Cortex-A7
+                Homepage:       http://www.marvell.com/multimedia-solutions/armada-1500-mini-plus/
 	88DE3100, Armada 1500
 		Design name:	BG2
 		Core:		Marvell PJ4B (ARMv7), Tauros3 L2CC