[ARM] eSATA SheevaPlug: correlate MPP to SD CD and SD WP

Accept SD CD and SD WP in accordance to
http://plugcomputer.org/data/docs/Sheeva-PowerPlug-V1.3-GTI-090906.pdf


on MPP 47 and 44 respectively on the eSATA SheevaPlug

Signed-off-by: John Holland <john.holland@cellent-fs.de>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
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