iio: accel: bmc150: Clarify combo modules in Kconfig

iio: accel: bmc150: Clarify combo modules in Kconfig

The Kconfig option currently says that all Bosch accelerometers
supported by the bmc150-accel driver are combo chips with both
accelerometer and magnetometer. This is wrong: actually only BMC150
is such a combo. The BMA* variants only contain an accelerometer
and the BMI055 actually is a accelerometer + gyroscope combo.

Clarify this in the help text and also make the list of supported
variants complete and sorted for consistency.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210611080903.14384-3-stephan@gerhold.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>