i2c: Make i2c_recover_bus() to return -EBUSY if bus recovery unimplemented

The i2c_recover_bus() returns -EOPNOTSUPP if bus recovery isn't wired up
by the bus driver, which the case for Tegra I2C driver for example. This
error code is then propagated to I2C client and might be confusing, thus
make i2c_recover_bus() to return -EBUSY instead.

Suggested-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>