[MTD] MAPS: Remove ITE 8172G and Globespan IVR MTD support

This patch has removed ITE 8172G and Globespan IVR MTD support.
These boards support have already been removed.

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Acked-by: Ralf Bächle <ralf@linux-mips.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>