MFD_*: swap ordering

This API is still young enough that I would expect no one to be dependant on
this yet... Swap the ordering while it's young to match Linux values to
potentially ease implementation of linuxolator syscall, being able to reuse
existing constants.

newlib/libc/sys/rtems/include/sys/mman.h

@@ -193,8 +193,8 @@
 /*
  * Flags for memfd_create().
  */
-#define	MFD_ALLOW_SEALING		0x00000001
-#define	MFD_CLOEXEC			0x00000002
+#define	MFD_CLOEXEC			0x00000001
+#define	MFD_ALLOW_SEALING		0x00000002
 
 /* UNSUPPORTED */
 #define	MFD_HUGETLB			0x00000004