i2c: gpio: OF gpio code does not handle defered probe case
When using device-tree and the i2c-gpio driver is called before the
GPIO node has been probed then it needs to correctly defer the probe
instead of returning a permanent error that the gpio numbers are not
valid.
This fixes the following error:
/i2c@2: invalid GPIO pins, sda=-517/scl=-517
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>