ARM: dts: enable touchscreen support on Cygnus

ARM: dts: enable touchscreen support on Cygnus

This patch enables touchscreen support on bcm958300k and bcm958305k.
Touchscreen is connected to these boards through the bcm9hmidc daughter
card, and therefore also adding bcm9hmidc.dtsi that describes the
daughter card

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Vikram Prakash <vikramp@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>