i2c: axxia: disable clks in case of failure in probe

axxia_i2c_probe() does not disable clock in case of failure
in i2c_add_adapter(). Also it ignores returned value from
clk_prepare_enable().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>