i2c: riic: fix restart condition

While modifying the driver to use the STOP interrupt, the completion of the
intermediate transfers need to wake the driver back up in order to initiate
the next transfer (restart condition). Otherwise you get never ending
interrupts and only the first transfer sent.

Fixes: 71ccea09

 ("i2c: riic: correctly finish transfers")
Reported-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>