ARM: AM57xx: Enable FIT for HS Devices

Enable FIT support for AM57xx platforms using the high-security (HS)
device variant.

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>

configs/am57xx_hs_evm_defconfig

@@ -37,3 +37,7 @@ CONFIG_SYS_NS16550=y
 CONFIG_USB=y
 CONFIG_USB_XHCI_HCD=y
 CONFIG_USB_XHCI_DWC3=y
+CONFIG_FIT=y
+CONFIG_SPL_OF_LIBFDT=y
+CONFIG_SPL_LOAD_FIT=y
+CONFIG_OF_LIST="am57xx-beagle-x15"