sh: export sh7723 VEU as VEU2H

Export sh7723 VEU hardware blocks as VEU2H. The sh7723 VEU2H differs
a bit from the sh7722 VEU so use different names for our UIO devices.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>