Remove the shim kernel crate

kernel/src/syscall/exit_group.rs

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use crate::{
+    prelude::*,
+    process::{do_exit_group, TermStatus},
+    syscall::SyscallReturn,
+};
+
+/// Exit all thread in a process.
+pub fn sys_exit_group(exit_code: u64, _ctx: &Context) -> Result<SyscallReturn> {
+    // Exit all thread in current process
+    let term_status = TermStatus::Exited(exit_code as _);
+    do_exit_group(term_status);
+    Ok(SyscallReturn::Return(0))
+}