thumbv7neon-unknown-linux-gnueabihf clippy fixes

[hkBst]

This takes care of all clippy warnings for this target except for:

$ cargo clippy --target=thumbv7neon-unknown-linux-gnueabihf
warning: casting raw pointers to the same type and constness is unnecessary (`*const i8` -> `*const i8`)
     --> crates/core_arch/src/arm_shared/neon/generated.rs:16634:15
      |
16634 |     vld1_v8i8(ptr as *const i8, crate::mem::align_of::<i8>() as i32)
      |               ^^^^^^^^^^^^^^^^ help: try: `ptr`
      |
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
      = note: `#[warn(clippy::unnecessary_cast)]` on by default

[snip]

warning: casting raw pointers to the same type and constness is unnecessary (`*const i8` -> `*const i8`)
     --> crates/core_arch/src/arm_shared/neon/generated.rs:26101:15
      |
26101 |     _vld4q_s8(a as *const i8, 1)
      |               ^^^^^^^^^^^^^^ help: try: `a`
      |
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

warning: `core_arch` (lib) generated 14 warnings
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.23s

Some of the variations need this cast, and I don't understand the format well enough to know how to deal with that.

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