ARM: imx8m: verdin-imx8mm: Drop bogus content from spl_board_init()

The current implementation of spl_board_init() USB boot handling is
not correct, the MX8MM BootROM v1 does not support SDP load when
re-entered from U-Boot SPL, it is up to U-Boot to perform the next
stage load using its own internal CI gadget driver and SDP protocol
implementation. Drop the spl_board_init() to let SPL continue with
normal load in case the SDP support is enabled.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/toradex/verdin-imx8mm/spl.c b/board/toradex/verdin-imx8mm/spl.c
index 59a3d9e..210665b 100644
--- a/board/toradex/verdin-imx8mm/spl.c
+++ b/board/toradex/verdin-imx8mm/spl.c
@@ -54,13 +54,6 @@
 void spl_board_init(void)
 {
 	arch_misc_init();
-
-	/* Serial download mode */
-	if (is_usb_boot()) {
-		puts("Back to ROM, SDP\n");
-		restore_boot_params();
-	}
-	puts("Normal Boot\n");
 }
 
 #ifdef CONFIG_SPL_LOAD_FIT