LibC: Move makedev(), major(), minor(), to sys/types.h

It's technically not specified by POSIX, but it appears most Unix-like
systems worth mentioning put those definitions there. Also, it's more
logical since the dev_t type is defined there.

Userland/Utilities/stat.cpp

@@ -13,6 +13,7 @@
 #include <pwd.h>
 #include <stdio.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <time.h>
 #include <unistd.h>