phy: tegra: xusb: remove a stray unlock

We used to take a lock in tegra186_utmi_bias_pad_power_on() but now we
have moved the lock into the caller.  Unfortunately, when we moved the
lock this unlock was left behind and it results in a double unlock.
Delete it now.

Fixes: b47158f ("phy: tegra: xusb: Use a bitmask for UTMI pad power state tracking")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/aAjmR6To4EnvRl4G@stanley.mountain
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/tegra/xusb-tegra186.c

@@ -656,8 +656,6 @@ static void tegra186_utmi_bias_pad_power_on(struct tegra_xusb_padctl *padctl)
 	} else {
 		clk_disable_unprepare(priv->usb2_trk_clk);
 	}
-
-	mutex_unlock(&padctl->lock);
 }
 
 static void tegra186_utmi_bias_pad_power_off(struct tegra_xusb_padctl *padctl)