The WP pins are ACTIVE_HIGH, fix it in the DTS.

Fixes: 2b41091b ("ARM: dts: alt: add SDHI0 and 1 support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>