pinctrl: intel: Read back TX buffer state

commit d68b42e30bbacd24354d644f430d088435b15e83 upstream.

In the same way as it's done in pinctrl-cherryview.c we would provide
a readback TX buffer state.

Fixes: 17fab473693 ("pinctrl: intel: Set pin direction properly")
Reported-by: "Bourque, Francis" <francis.bourque@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: "Bourque, Francis" <francis.bourque@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Anthony de Boer <adb@adb.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>