iio: st_pressure: Support i2c probe using acpi

Compatible strings are not available on ACPI based systems. This patch adds
support to use DSDT information read from platform BIOS instead for probing
st pressure sensors.

Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>