Elevate .text.syscall to .privileged

It turns out adding OpenBSD msyscall() origin verification broke the
--ftrace flag. The executable needs to issue raw syscalls while it's
rewriting itself. So they need to be in the same section, and that's
just plain simpler too.

libc/calls/mprotect.greg.c

@@ -34,7 +34,7 @@ extern __msabi typeof(VirtualProtect) *const __imp_VirtualProtect;
  * @return 0 on success, or -1 w/ errno
  * @see mmap()
  */
-textsyscall int mprotect(void *addr, uint64_t len, int prot) {
+privileged int mprotect(void *addr, uint64_t len, int prot) {
   bool cf;
   int64_t rc;
   uint32_t oldprot;

libc/calls/netbsdtramp.S

@@ -17,7 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.h"
-.text.syscall
+.privileged
 
 __restore_rt_netbsd:
 	mov	%r15,%rdi