iio: magnetometer: bmc150: Drop ACPI_PTR() usage

iio: magnetometer: bmc150: Drop ACPI_PTR() usage

Avoiding unused variable warnings when using this macro adds
complexity that in simple cases like this one is not justified
for the small saving in data.

Drop unused linux/acpi.h includes.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312040109.Csnmqnb2-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202311171116.47sUbZV5-lkp@intel.com/
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20231231183514.566609-19-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>