This adds i2c bus recovery to the mv64xxx driver.

Implement bus recovery to recover from SCL/SDA stuck low.

This uses the generic recovery function, setting the clock/data lines as
GPIO pins, and sending 9 clocks to try and recover the bus.
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
[wsa: added some curly braces]
Signed-off-by: Wolfram Sang <wsa@kernel.org>