db-mv784mp-gp: Rename CONFIG_DB_784MP_GP to CONFIG_TARGET_DB_MV784MP_GP

The value CONFIG_DB_784MP_GP is only used in the DDR code to refer to
CONFIG_TARGET_DB_MV784MP_GP so just use that second value directly.

Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/ddr/marvell/axp/ddr3_axp.h b/drivers/ddr/marvell/axp/ddr3_axp.h
index 970651f..a14c766 100644
--- a/drivers/ddr/marvell/axp/ddr3_axp.h
+++ b/drivers/ddr/marvell/axp/ddr3_axp.h
@@ -37,7 +37,7 @@
 #define ECC_SUPPORT
 #endif
 #define NEW_FABRIC_TWSI_ADDR		0x4E
-#ifdef CONFIG_DB_784MP_GP
+#ifdef CONFIG_TARGET_DB_MV784MP_GP
 #define BUS_WIDTH_ECC_TWSI_ADDR		0x4E
 #else
 #define BUS_WIDTH_ECC_TWSI_ADDR		0x4F