Remove target features in VxWokrs RISC-V spec as they are automatically added by clang

Author: biabbas

compiler/rustc_target/src/spec/targets/riscv32_wrs_vxworks.rs

@@ -16,7 +16,6 @@ pub(crate) fn target() -> Target {
             cpu: "generic-rv32".into(),
             llvm_abiname: "ilp32d".into(),
             max_atomic_width: Some(32),
-            features: "+m,+a,+f,+d,+c,+zicsr".into(),
             stack_probes: StackProbeType::Inline,
             ..base::vxworks::opts()
         },

compiler/rustc_target/src/spec/targets/riscv64_wrs_vxworks.rs

@@ -16,7 +16,6 @@ pub(crate) fn target() -> Target {
             cpu: "generic-rv64".into(),
             llvm_abiname: "lp64d".into(),
             max_atomic_width: Some(64),
-            features: "+m,+a,+f,+d,+c,+zicsr".into(),
             stack_probes: StackProbeType::Inline,
             ..base::vxworks::opts()
         },