i2c: pca-platform: propagate error from i2c_pca_add_numbered_bus

Rather than returning -ENODEV if i2c_pca_add_numbered_bus() fails,
propagate the error to aid debugging.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>