sparc32,leon: Added __init declaration to leon_flush_needed()

The function leon_flush_needed() is called only during bootup from another
__init function. Therefore, we can also add __init to leon_flush_needed().

Signed-off-by: Matthias Rosenfelder <rosenfelder.lkml@googlemail.com>
Acked-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>