i2c: recovery: refactor recovery function

After exiting the while loop, we checked if recovery was successful and
sent a STOP to the clients. Meanwhile however, we send a STOP after
every pulse, so it is not needed after the loop. If we move the check
for a free bus to the end of the while loop, we can shorten and simplify
the logic. It is still ensured that at least one STOP will be sent to
the wire even if SDA was not stuck low.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>