mprotect and msync take void*, not const void*.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/mprotect.html
http://pubs.opengroup.org/onlinepubs/9699919799/functions/msync.html

Change-Id: Ie26195e2e382c1387037c7ee5cd90b3963220328
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index 934963f..79f1faf 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -57,8 +57,8 @@
 void* mmap64(void*, size_t, int, int, int, off64_t) __INTRODUCED_IN(21);
 
 int munmap(void*, size_t);
-int msync(const void*, size_t, int);
-int mprotect(const void*, size_t, int);
+int msync(void*, size_t, int);
+int mprotect(void*, size_t, int);
 void* mremap(void*, size_t, size_t, int, ...);
 
 int mlockall(int) __INTRODUCED_IN(17);