board: ti: am64x: Switch to standard boot flow

Switch to using bootstd. Note with this change, we will stop using
distro_bootcmd and instead depend entirely on bootflow method of
starting the system up.

Drop header files that are no longer needed in am64x_evm.h.
k3_dfu.h is available via k3_dfu.env in am64x.env.

Drop unused macro CFG_SYS_SDRAM_BASE1.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Nishanth Menon <nm@ti.com>
diff --git a/configs/am64x_evm_a53_defconfig b/configs/am64x_evm_a53_defconfig
index e92a651..20b101a 100644
--- a/configs/am64x_evm_a53_defconfig
+++ b/configs/am64x_evm_a53_defconfig
@@ -30,8 +30,9 @@
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SPL_LOAD_FIT=y
 CONFIG_SPL_LOAD_FIT_ADDRESS=0x81000000
-CONFIG_DISTRO_DEFAULTS=y
-CONFIG_BOOTCOMMAND="run envboot; run distro_bootcmd;"
+CONFIG_BOOTSTD_FULL=y
+CONFIG_BOOTSTD_DEFAULTS=y
+CONFIG_BOOTCOMMAND="run envboot; bootflow scan -lb"
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_SPL_MAX_SIZE=0x180000
 CONFIG_SPL_HAS_BSS_LINKER_SECTION=y