ARM: mvebu: rename armada-385-amc.dts to armada-385-db-88f6820-amc.dts

This board was added to u-boot first but the Linux maintainers requested
a more descriptive name. Rename the file to match the Linux usage and
update the board defconfig.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/configs/db-88f6820-amc_defconfig b/configs/db-88f6820-amc_defconfig
index dcf2a25..e8ba518 100644
--- a/configs/db-88f6820-amc_defconfig
+++ b/configs/db-88f6820-amc_defconfig
@@ -41,7 +41,7 @@
 CONFIG_EFI_PARTITION=y
 # CONFIG_PARTITION_UUIDS is not set
 # CONFIG_SPL_PARTITION_UUIDS is not set
-CONFIG_DEFAULT_DEVICE_TREE="armada-385-amc"
+CONFIG_DEFAULT_DEVICE_TREE="armada-385-db-88f6820-amc"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_USE_ENV_SPI_MAX_HZ=y
 CONFIG_ENV_SPI_MAX_HZ=50000000