Fix fastboot boot address

Fastboot loads an image at CONFIG_FASTBOOT_BUF_ADDR, but currently
tells do_bootm() to look for an image at $loadaddr.  This breaks if
CONFIG_FASTBOOT_BUF_ADDR is different from the current user-set
loadaddr.

Instead, tell do_bootm() to pick up the image where it was laoded.

Signed-off-by: Peter Chubb <peter.chubb@data61.csiro.au>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Steve Rae <steve.rae@raedomain.com>

drivers/usb/gadget/f_fastboot.c

@@ -561,7 +561,7 @@ static void do_bootm_on_complete(struct usb_ep *ep, struct usb_request *req)
 
 	puts("Booting kernel..\n");
 
-	sprintf(boot_addr_start, "0x%lx", load_addr);
+	sprintf(boot_addr_start, "0x%lx", CONFIG_FASTBOOT_BUF_ADDR);
 	do_bootm(NULL, 0, 2, bootm_args);
 
 	/* This only happens if image is somehow faulty so we start over */