In omap_i2c_xfer(), ensure pm_runtime_put() is called, even on
failure.

Without this, after a failed xfer, the runtime PM usecount will have
been incremented, but not decremented causing the usecount to never
reach zero after a failure.  This keeps the device always runtime PM
enabled which keeps the enclosing power domain active, and prevents
full-chip retention/off from happening during idle.
Signed-off-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>