x1000: don't add pointless '1' after SPL signature

I added this because it is present on the FiiO M3K's SPL, but nothing
in Ingenic docs suggest this means anything.

Just get rid of it; the M3K boots fine without it.

Change-Id: I2e480b8c0ada386b0e772db49c0a7ebd32ffc7ea

tools/mkspl-x1000.c

@@ -136,7 +136,6 @@ void do_flash(const uint8_t* spl_code,
     uint8_t hdr_buf[SPL_HEADER_SIZE];
     memset(hdr_buf, 0, SPL_HEADER_SIZE);
     memcpy(hdr_buf, &sig, sizeof(sig));
-    hdr_buf[sizeof(sig)] = 1; /* ??? used in the FiiO M3K */
 
     /* create null key */
     uint8_t null_key[SPL_KEY_SIZE];