ARM: davinci: da850: add con_id for the SATA clock

The ahci-da850 SATA driver is now capable of retrieving clocks by
con_id. Add the connection id for the sysclk2-derived SATA clock.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>