Replace chatty syscall stubs with silent variant

These syscalls have fallbacks in musl which we do implement but they are
only invoked after they return ENOSYS, which fills dmesg with lots of
spam.

kernel/calls.c

@@ -6,10 +6,16 @@
 #include "kernel/signal.h"
 #include "kernel/task.h"
 
-dword_t syscall_stub() {
+dword_t syscall_stub(void) {
     return _ENOSYS;
 }
-dword_t syscall_success_stub() {
+// While identical, this version of the stub doesn't log below. Use this for
+// syscalls that are optional (i.e. fallback on something else) but called
+// frequently.
+dword_t syscall_silent_stub(void) {
+    return _ENOSYS;
+}
+dword_t syscall_success_stub(void) {
     return 0;
 }
 
@@ -238,9 +244,9 @@ syscall_t syscall_table[] = {
     [373] = (syscall_t) sys_shutdown,
     [375] = (syscall_t) syscall_stub, // membarrier
     [377] = (syscall_t) sys_copy_file_range,
-    [383] = (syscall_t) syscall_stub, // statx
+    [383] = (syscall_t) syscall_silent_stub, // statx
     [384] = (syscall_t) sys_arch_prctl,
-    [439] = (syscall_t) syscall_stub, // faccessat2
+    [439] = (syscall_t) syscall_silent_stub, // faccessat2
 };
 
 #define NUM_SYSCALLS (sizeof(syscall_table) / sizeof(syscall_table[0]))
@@ -315,7 +321,7 @@ void handle_interrupt(int interrupt) {
     unlock(&group->lock);
 }
 
-void dump_maps() {
+void dump_maps(void) {
     extern void proc_maps_dump(struct task *task, struct proc_data *buf);
     struct proc_data buf = {};
     proc_maps_dump(current, &buf);