arm: mvebu: Add basic support for Armada 375 eval board db-88f6720

This patch adds basic support for the Marvell A375 eval board. Tested
are the following interfaces:
- I2C
- SPI
- SPI NOR
- Ethernet (mvpp2), port 0 & 1

Currently the A375 SerDes and DDR3 init code is not intergrated. So
the SPL U-Boot is not fully functional.

Right now, this A375 mainline U-Boot can only be used by chainloading
it via the original Marvell U-Boot. This can be done via this
command:

=> tftpboot 00800000 a375/u-boot-dtb.bin;go 00800000

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>
diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 96a3313..220886a 100644
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -1,5 +1,8 @@
 if ARCH_MVEBU
 
+config ARMADA_375
+	bool
+
 config ARMADA_38X
 	bool
 
@@ -23,13 +26,17 @@
 	select ARMADA_38X
 
 choice
-	prompt "Marvell MVEBU (Armada XP/38x) board select"
+	prompt "Marvell MVEBU (Armada XP/375/38x) board select"
 	optional
 
 config TARGET_CLEARFOG
 	bool "Support ClearFog"
 	select DB_88F6820_GP
 
+config TARGET_DB_88F6720
+	bool "Support DB-88F6720 Armada 375"
+	select ARMADA_375
+
 config TARGET_DB_88F6820_GP
 	bool "Support DB-88F6820-GP"
 	select DB_88F6820_GP
@@ -54,6 +61,7 @@
 
 config SYS_BOARD
 	default "clearfog" if TARGET_CLEARFOG
+	default "db-88f6720" if TARGET_DB_88F6720
 	default "db-88f6820-gp" if TARGET_DB_88F6820_GP
 	default "db-mv784mp-gp" if TARGET_DB_MV784MP_GP
 	default "ds414" if TARGET_DS414
@@ -62,6 +70,7 @@
 
 config SYS_CONFIG_NAME
 	default "clearfog" if TARGET_CLEARFOG
+	default "db-88f6720" if TARGET_DB_88F6720
 	default "db-88f6820-gp" if TARGET_DB_88F6820_GP
 	default "db-mv784mp-gp" if TARGET_DB_MV784MP_GP
 	default "ds414" if TARGET_DS414
@@ -70,6 +79,7 @@
 
 config SYS_VENDOR
 	default "Marvell" if TARGET_DB_MV784MP_GP
+	default "Marvell" if TARGET_DB_88F6720
 	default "Marvell" if TARGET_DB_88F6820_GP
 	default "solidrun" if TARGET_CLEARFOG
 	default "Synology" if TARGET_DS414