pwmchip_add() returns zero on success and a negative value on error,
so the condition of the check must be inverted.
Signed-off-by: NBeniamino Galvani <b.galvani@gmail.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>