am437x: Add am57xx_evm_defconfig using CONFIG_DM

Import various DT files for am57xx-beagle-x15 from
Linux Kernel v4.2
Add config file for this board, enable DM, DM_GPIO,
DM_SERIAL and DM_MMC.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
diff --git a/configs/am57xx_evm_defconfig b/configs/am57xx_evm_defconfig
new file mode 100644
index 0000000..f6566bf
--- /dev/null
+++ b/configs/am57xx_evm_defconfig
@@ -0,0 +1,19 @@
+CONFIG_ARM=y
+CONFIG_OMAP54XX=y
+CONFIG_TARGET_BEAGLE_X15=y
+CONFIG_DEFAULT_DEVICE_TREE="am57xx-beagle-x15"
+CONFIG_SPL=y
+CONFIG_SPL_STACK_R=y
+CONFIG_SPL_STACK_R_ADDR=0x82000000
+CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=3"
+# CONFIG_CMD_IMLS is not set
+# CONFIG_CMD_FLASH is not set
+# CONFIG_CMD_SETEXPR is not set
+# CONFIG_CMD_NFS is not set
+CONFIG_OF_CONTROL=y
+CONFIG_DM=y
+CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_BAR=y
+CONFIG_DM_GPIO=y
+CONFIG_DM_SERIAL=y
+CONFIG_DM_MMC=y