feat: Target features for 1st group of RISC-V Bitmanip extensions

These use the same names as LLVM and is_riscv_feature_detected!:
- zba (address generation instructions)
- zbb (basic bit manipulation)
- zbc (carry-less multiplication)
- zbs (single-bit manipulation)

Author: tux3

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -227,6 +227,10 @@ const RISCV_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("zhinxmin", Some(sym::riscv_target_feature)),
     ("zfh", Some(sym::riscv_target_feature)),
     ("zfhmin", Some(sym::riscv_target_feature)),
+    ("zba", Some(sym::riscv_target_feature)),
+    ("zbb", Some(sym::riscv_target_feature)),
+    ("zbc", Some(sym::riscv_target_feature)),
+    ("zbs", Some(sym::riscv_target_feature)),
     ("zbkb", Some(sym::riscv_target_feature)),
     ("zbkc", Some(sym::riscv_target_feature)),
     ("zbkx", Some(sym::riscv_target_feature)),