sched: fix cpu_set_t ordering in generated header

The CPU_* inline functions in after_includes referenced cpu_set_t
before cbindgen generated its definition. Move the full struct typedef
into after_includes before the inline functions, and remove cpu_set_t
from the [export] list to avoid duplicate definitions.

src/header/sched/cbindgen.toml

@@ -11,6 +11,12 @@ after_includes = """
 #include <bits/timespec.h> // for timespec
 
 #define CPU_SETSIZE 1024
+
+/* cpu_set_t must be defined BEFORE the CPU_* inline functions */
+typedef struct cpu_set_t {
+  uint64_t __bits[16];
+} cpu_set_t;
+
 static inline void CPU_ZERO(cpu_set_t *set) {
     for (int i = 0; i < 16; i++) set->__bits[i] = 0;
 }
@@ -44,7 +50,6 @@ prefix_with_name = true
 [export]
 include = [
     "sched_param",
-    "cpu_set_t",
     "sched_get_priority_max",
     "sched_get_priority_min",
     "sched_getparam",