Removes alignment requirement in st3

Author: awxkee

crates/core_arch/src/macros.rs

@@ -280,6 +280,7 @@ macro_rules! deinterleaving_load {
         let arr: Arr = std::array::from_fn(|x| $crate::ptr::read_unaligned(($ptr as *const $elem).add(x)));
         // NOTE: repr(simd) adds padding to make the total size a power of two.
         // Hence writing W to ptr might write out of bounds.
+        type W = Simd<$elem, { $lanes * 3 }>;
         let w: W = W::from_array(arr);
 
         let v0: V = simd_shuffle!(w, w, deinterleave_mask::<$lanes, 3, 0>());