Rollup merge of rust-lang#90688 - SparrowLii:dotprod, r=Amanieu

enable `dotprod` target feature in arm

To implement `vdot` neon insturction in stdarch, we need to enable `dotprod` target feature in arm in rustc.
r? `@Amanieu`

Author: JohnTitor

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -20,6 +20,7 @@ const ARM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("aes", Some(sym::arm_target_feature)),
     ("sha2", Some(sym::arm_target_feature)),
     ("i8mm", Some(sym::arm_target_feature)),
+    ("dotprod", Some(sym::arm_target_feature)),
     ("v5te", Some(sym::arm_target_feature)),
     ("v6", Some(sym::arm_target_feature)),
     ("v6k", Some(sym::arm_target_feature)),