Switch the driver from legacy gpio API (that uses flat GPIO numbering)
to the newer gpiod API (which used descriptors and respects line
polarities specified in ACPI or device tree).

Because gpio handling code for SPI and I2C variants duplicates each
other it is moved into the core code for the driver.

Also, it seems that the driver never assigned tpm_dev->io_lpcpd in the
past, so gpio-based power management was most likely not working ever.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>