iio: pressure: bmp280: add support for BMP180

This adds support for the BMP180 to the bmp280 iio driver.

The BMP180 has already been supported by misc/bmp085 driver but it
doesn't use iio framework.  This change adds the kconfig dependency
not to be selected both of them in order to avoid any issues.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Vlad Dogaru <vlad.dogaru@intel.com>
Cc: Christoph Mair <christoph.mair@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>