Remove stakeWithPermit function and its related interface.

src/KTONStakingRewards.sol

@@ -20,7 +20,7 @@ contract StakingRewards is IStakingRewards, RewardsDistributionRecipient, Reentr
     IERC20 public stakingToken;
     uint256 public periodFinish = 0;
     uint256 public rewardRate = 0;
-    uint256 public rewardsDuration = 60 days;
+    uint256 public rewardsDuration = 7200;
     uint256 public lastUpdateTime;
     uint256 public rewardPerTokenStored;
 
@@ -76,18 +76,6 @@ contract StakingRewards is IStakingRewards, RewardsDistributionRecipient, Reentr
 
     /* ========== MUTATIVE FUNCTIONS ========== */
 
-    function stakeWithPermit(uint256 amount, uint deadline, uint8 v, bytes32 r, bytes32 s) external nonReentrant updateReward(msg.sender) {
-        require(amount > 0, "Cannot stake 0");
-        _totalSupply = _totalSupply.add(amount);
-        _balances[msg.sender] = _balances[msg.sender].add(amount);
-
-        // permit
-        IUniswapV2ERC20(address(stakingToken)).permit(msg.sender, address(this), amount, deadline, v, r, s);
-
-        stakingToken.safeTransferFrom(msg.sender, address(this), amount);
-        emit Staked(msg.sender, amount);
-    }
-
     function stake(uint256 amount) external nonReentrant updateReward(msg.sender) {
         require(amount > 0, "Cannot stake 0");
         _totalSupply = _totalSupply.add(amount);
@@ -160,7 +148,3 @@ contract StakingRewards is IStakingRewards, RewardsDistributionRecipient, Reentr
     event Withdrawn(address indexed user, uint256 amount);
     event RewardPaid(address indexed user, uint256 reward);
 }
-
-interface IUniswapV2ERC20 {
-    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
-}