arm: ls1021atwr: Add distro boot support

This patch includes common config_distro_defaults.h and
config_distro_bootcmd.h for u-boot enviroments to support distro boot
which automatically scan boot.scr from storage devices(e.g.
SD/USB/SATA/SCSI disk) and execute autoboot script on LS1021ATWR board.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@nxp.com>
Signed-off-by: Alison Wang <alison.wang@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/configs/ls1021atwr_nor_defconfig b/configs/ls1021atwr_nor_defconfig
index cdbf5a2..29d6ea1 100644
--- a/configs/ls1021atwr_nor_defconfig
+++ b/configs/ls1021atwr_nor_defconfig
@@ -45,3 +45,4 @@
 CONFIG_USB_STORAGE=y
 CONFIG_VIDEO_FSL_DCU_FB=y
 # CONFIG_VIDEO_SW_CURSOR is not set
+CONFIG_DISTRO_DEFAULTS=y
diff --git a/configs/ls1021atwr_sdcard_ifc_defconfig b/configs/ls1021atwr_sdcard_ifc_defconfig
index b87a6d3..8647365 100644
--- a/configs/ls1021atwr_sdcard_ifc_defconfig
+++ b/configs/ls1021atwr_sdcard_ifc_defconfig
@@ -57,3 +57,4 @@
 CONFIG_USB_STORAGE=y
 CONFIG_VIDEO_FSL_DCU_FB=y
 # CONFIG_VIDEO_SW_CURSOR is not set
+CONFIG_DISTRO_DEFAULTS=y
diff --git a/configs/ls1021atwr_sdcard_qspi_defconfig b/configs/ls1021atwr_sdcard_qspi_defconfig
index 9ab9e25..b254f3b 100644
--- a/configs/ls1021atwr_sdcard_qspi_defconfig
+++ b/configs/ls1021atwr_sdcard_qspi_defconfig
@@ -64,3 +64,4 @@
 CONFIG_USB_STORAGE=y
 CONFIG_VIDEO_FSL_DCU_FB=y
 # CONFIG_VIDEO_SW_CURSOR is not set
+CONFIG_DISTRO_DEFAULTS=y