arm: mvebu: dts: Makefile: Compile Armada 375 dtb in a separate step

This patch changes the compilation, so that the Armada 375 board(s) are
compiled in a separate step. This is necessary for the timer dts
conversion, as A375 has a different / timer description in the dts.

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Tony Dinh <mibodhi@gmail.com>

arch/arm/dts/Makefile

@@ -233,8 +233,11 @@ dtb-$(CONFIG_ARCH_TEGRA) += tegra20-harmony.dtb \
 	tegra210-p3450-0000.dtb
 
 ifdef CONFIG_ARMADA_32BIT
+ifdef CONFIG_ARMADA_375
+dtb-$(CONFIG_ARCH_MVEBU) +=			\
+	armada-375-db.dtb
+else
 dtb-$(CONFIG_ARCH_MVEBU) +=			\
-	armada-375-db.dtb			\
 	armada-385-atl-x530.dtb			\
 	armada-385-atl-x530DP.dtb		\
 	armada-385-db-88f6820-amc.dtb		\
@@ -254,6 +257,7 @@ dtb-$(CONFIG_ARCH_MVEBU) +=			\
 	armada-xp-maxbcm.dtb			\
 	armada-xp-synology-ds414.dtb		\
 	armada-xp-theadorable.dtb
+endif
 else
 dtb-$(CONFIG_ARCH_MVEBU) +=			\
 	armada-3720-db.dtb			\