usb: gadget: f_sdp: Add missing spl_board_prepare_for_boot() call

The spl_board_prepare_for_boot() should be called before jump_to_image_no_args()
to perform board-specific deinitialization before jumping to the next stage.
This board-specific deinitialization can be very much anything, e.g. disable
dcache in case it was enabled, or such.

Add the missing spl_board_prepare_for_boot() call into f_sdp .

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/gadget/f_sdp.c b/drivers/usb/gadget/f_sdp.c
index 9ea43f2..4da5a16 100644
--- a/drivers/usb/gadget/f_sdp.c
+++ b/drivers/usb/gadget/f_sdp.c
@@ -865,6 +865,7 @@
 			struct spl_image_info spl_image = {};
 			struct spl_boot_device bootdev = {};
 			spl_parse_image_header(&spl_image, &bootdev, header);
+			spl_board_prepare_for_boot();
 			jump_to_image_no_args(&spl_image);
 #else
 			/* In U-Boot, allow jumps to scripts */