arm: mvebu: create generic 88F6820 config option

88F6820 is a specific Armada-38x chip that is used on the DB-88F6820-GP
board. Rather than having DB_88F6820_GP and TARGET_DB_88F6820_GP which
selects the former. Rename DB_88F6820_GP to 88F6820 so that other boards
using the 88F6820 can be added.

Stefan:
Change 88F6820 for clearfog as well.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 220886a..8ce0c9e 100644
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -21,7 +21,7 @@
 	bool
 	select ARMADA_XP
 
-config DB_88F6820_GP
+config 88F6820
 	bool
 	select ARMADA_38X
 
@@ -31,7 +31,7 @@
 
 config TARGET_CLEARFOG
 	bool "Support ClearFog"
-	select DB_88F6820_GP
+	select 88F6820
 
 config TARGET_DB_88F6720
 	bool "Support DB-88F6720 Armada 375"
@@ -39,7 +39,7 @@
 
 config TARGET_DB_88F6820_GP
 	bool "Support DB-88F6820-GP"
-	select DB_88F6820_GP
+	select 88F6820
 
 config TARGET_DB_MV784MP_GP
 	bool "Support db-mv784mp-gp"