i40e: little endian only valid checksums

The calculation of the checksum can fail.
So move converting the checksum to little endian
to inside the return status check.
Signed-off-by: Tom Rix <trix@redhat.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_nvm.c

@@ -682,10 +682,11 @@ i40e_status i40e_update_nvm_checksum(struct i40e_hw *hw)
 	__le16 le_sum;
 
 	ret_code = i40e_calc_nvm_checksum(hw, &checksum);
-	le_sum = cpu_to_le16(checksum);
-	if (!ret_code)
+	if (!ret_code) {
+		le_sum = cpu_to_le16(checksum);
 		ret_code = i40e_write_nvm_aq(hw, 0x00, I40E_SR_SW_CHECKSUM_WORD,
 					     1, &le_sum, true);
+	}
 
 	return ret_code;
 }