iio: pressure: bmp280: Make error checks consistent

The form 'if (ret)' is used in this driver in order to check
for returned error values. There are also some places that
'if (ret < 0)' is used but for no specific reason. Change
them to 'if (ret)' to make the driver more consistent.

Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://lore.kernel.org/r/20240508165207.145554-4-vassilisamir@gmail.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>