ice: Fix package download algorithm

Previously, the driver assumed that all signature segments would contain
one or more buffers to download. In the future, there will be signature
segments that will contain no buffers to download.

Correct download flow to allow for signature segments that have zero
download buffers and skip the download in this case.

Fixes: 3cbdb034 ("ice: Add support for E830 DDP package segment")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Dan Nowlin <dan.nowlin@intel.com>
Signed-off-by: Paul Greenwalt <paul.greenwalt@intel.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://lore.kernel.org/r/20240508171908.2760776-1-anthony.l.nguyen@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/ice/ice_ddp.c

@@ -1424,14 +1424,14 @@ ice_dwnld_sign_and_cfg_segs(struct ice_hw *hw, struct ice_pkg_hdr *pkg_hdr,
 		goto exit;
 	}
 
-	conf_idx = le32_to_cpu(seg->signed_seg_idx);
-	start = le32_to_cpu(seg->signed_buf_start);
 	count = le32_to_cpu(seg->signed_buf_count);
-
 	state = ice_download_pkg_sig_seg(hw, seg);
-	if (state)
+	if (state || !count)
 		goto exit;
 
+	conf_idx = le32_to_cpu(seg->signed_seg_idx);
+	start = le32_to_cpu(seg->signed_buf_start);
+
 	state = ice_download_pkg_config_seg(hw, pkg_hdr, conf_idx, start,
 					    count);