Remove __overloadable/__RENAME_CLANG

Now that we have a clang that supports transparent overloads, we can
kill all of this cruft, and restore our upstream sources to their
untouched glory. Woohoo!

Bug: 12231437
Test: Built aosp_marlin; no obvious patch-related aosp_mips issues.
Change-Id: I520a19d014f12137f80e43f973dccd6711c571cd
diff --git a/libc/include/poll.h b/libc/include/poll.h
index 9ca1cf8..6a8f757 100644
--- a/libc/include/poll.h
+++ b/libc/include/poll.h
@@ -38,8 +38,8 @@
 
 typedef unsigned int nfds_t;
 
-int poll(struct pollfd* __fds, nfds_t __count, int __timeout_ms) __overloadable __RENAME_CLANG(poll);
-int ppoll(struct pollfd* __fds, nfds_t __count, const struct timespec* __timeout, const sigset_t* __mask) __overloadable __RENAME_CLANG(ppoll) __INTRODUCED_IN(21);
+int poll(struct pollfd* __fds, nfds_t __count, int __timeout_ms);
+int ppoll(struct pollfd* __fds, nfds_t __count, const struct timespec* __timeout, const sigset_t* __mask) __INTRODUCED_IN(21);
 int ppoll64(struct pollfd* __fds, nfds_t __count, const struct timespec* __timeout, const sigset64_t* __mask) __INTRODUCED_IN(28);
 
 #if defined(__BIONIC_INCLUDE_FORTIFY_HEADERS)