message: Remove an unnecessary lint workaround and comment register ABI names.
diff: @@ -6,30 +6,29 @@ impl RawSyscalls for crate::TockSyscalls {
  #[cfg(not(any(target_feature = "d", target_feature = "f")))]
  fn raw_yield(r0_in: YieldType) -> u32 {
  let mut r0 = r0_in as u32;
  - let mut _a4 = 0;
  unsafe {
  asm!("ecall",
  - // x0 is a constant.
  + // x0 is the zero register.
  lateout("x1") _, // Return address
  // x2-x4 are stack, global, and thread pointers. sp is
  // callee-saved.
  - lateout("x5") _,
  - lateout("x6") _,
  - lateout("x7") _,
  - // x8 and x9 are callee-saved.
  - inlateout("x10") r0,
  - lateout("x11") _,
  - lateout("x12") _,
  - lateout("x13") _,
  - inlateout("x14") _a4,
  - lateout("x15") _,
  - lateout("x16") _,
  - lateout("x17") _,
  - // x18-27 (aka s2-s11) are callee-saved
  - lateout("x28") _,
  - lateout("x29") _,
  - lateout("x30") _,
  - lateout("x31") _,
  + lateout("x5") _, // t0
  + lateout("x6") _, // t1
  + lateout("x7") _, // t2
  + // x8 and x9 are s0 and s1 and are callee-saved.
  + inlateout("x10") r0, // a0
  + lateout("x11") _, // a1
  + lateout("x12") _, // a2
  + lateout("x13") _, // a3
  + inlateout("x14") 0 => _, // a4
  + lateout("x15") _, // a5
  + lateout("x16") _, // a6
  + lateout("x17") _, // a7
  + // x18-27 are s2-s11 and are callee-saved
  + lateout("x28") _, // t3
  + lateout("x29") _, // t4
  + lateout("x30") _, // t5
  + lateout("x31") _, // t6
  );
  }
  r0
  