imx6: ventana: add default kernel modules for GSC

All Gateworks Ventana boards have a Gateworks System Controller
which emulates the following:
 - ds1672 RTC
 - pca953x GPIO expander
 - hardware monitor
 - at24 eeprom

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 39112