return type of read_i2c() is int not u32. As the assignments to status
are consistent with int here its type is changed to int.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>