Silence a few warnings from clippy

These were flagged by `cargo clippy`:

    warning: the operation is ineffective. Consider reducing it to `number`
    warning: this function has too many arguments (8/7)
    warning: you should consider adding a `Default` implementation for
             `phy::loopback::Loopback`

I like the code better as it is.

src/lib.rs

@@ -92,6 +92,7 @@ compile_error!("at least one socket needs to be enabled"); */
 #![allow(clippy::manual_non_exhaustive)]
 #![allow(clippy::match_like_matches_macro)]
 #![allow(clippy::redundant_field_names)]
+#![allow(clippy::identity_op)]
 
 #[cfg(feature = "alloc")]
 extern crate alloc;

src/phy/loopback.rs

@@ -19,6 +19,7 @@ pub struct Loopback {
     queue: VecDeque<Vec<u8>>,
 }
 
+#[allow(clippy::new_without_default)]
 impl Loopback {
     /// Creates a loopback device.
     ///

src/wire/ip.rs

@@ -108,6 +108,7 @@ impl Address {
 
     /// Create an address wrapping an IPv6 address with the given octets.
     #[cfg(feature = "proto-ipv6")]
+    #[allow(clippy::too_many_arguments)]
     pub fn v6(a0: u16, a1: u16, a2: u16, a3: u16,
               a4: u16, a5: u16, a6: u16, a7: u16) -> Address {
         Address::Ipv6(Ipv6Address::new(a0, a1, a2, a3, a4, a5, a6, a7))

src/wire/ipv6.rs

@@ -47,6 +47,7 @@ impl Address {
                  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01]);
 
     /// Construct an IPv6 address from parts.
+    #[allow(clippy::too_many_arguments)]
     pub fn new(a0: u16, a1: u16, a2: u16, a3: u16,
                a4: u16, a5: u16, a6: u16, a7: u16) -> Address {
         let mut addr = [0u8; 16];