ARM: shmobile: lager: enable HS-USB

Enable HS-USB device for the Lager board, defining the GPIO that the driver
should check when probing. Since this board doesn't have the OTG ID pin, we
assume that GP5_18 (USB0_PWEN) is an ID pin because it is 1 when the SW5 is
in position 2-3 (meaning USB function) and 0 in other positions.

Note that there will be pinctrl-related error messages if both internal PCI
and HS-USB drivers are enabled but they should be just ignored.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
[Sergei: added pin node and prop, moved device node, fixed summary, supplemented
changelog]
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>