ARM: OMAP: Release i2c_adapter after use (Siemens SX1)

Each call to i2c_get_adapter() must be followed by a call to
i2c_put_adapter() to release the grabbed reference. Otherwise the
reference count grows forever and the adapter can never be
unregistered.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Vladimir Ananiev <vovan888@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>