board: ti: am62x: Set fdtfile from C code instead of findfdt script

Stop using the findfdt script and switch to setting the fdtfile from
C code.

While at this, replace findfdt in environment with a warning as it is
no longer needed

Reviewed-by: Jonathan Humphreys <j-humphreys@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/configs/am62x_evm_a53_defconfig b/configs/am62x_evm_a53_defconfig
index 457931f..a39b82d 100644
--- a/configs/am62x_evm_a53_defconfig
+++ b/configs/am62x_evm_a53_defconfig
@@ -32,6 +32,7 @@
 CONFIG_BOOTSTD_DEFAULTS=y
 CONFIG_SYS_BOOTM_LEN=0x800000
 CONFIG_BOOTCOMMAND="run envboot; bootflow scan -lb"
+CONFIG_BOARD_LATE_INIT=y
 CONFIG_SPL_MAX_SIZE=0x58000
 CONFIG_SPL_HAS_BSS_LINKER_SECTION=y
 CONFIG_SPL_BSS_START_ADDR=0x80c80000