[MTD] ESB2 check for closed ROM window

Add checking for closed ROM window on Intel ESB2 Southbridge.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>