ARM: shmobile: henninger: add SDHI0/2 DT support

Define the Henninger board dependent part of the SDHI0/2 device nodes along with
the necessary voltage regulators (note that the Vcc regulators are dummy -- they
are required but don't actually exist on the board). Also, GPIOs have to be used
for the CD and WP signals due to the SDHI driver constraints...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>