drm/i915/dsi: Combine checks in mipi_exec_gpio()

For a couple of cases the branches call the same bxt_gpio_set_value().
As Ville suggested they can be combined by dropping the DISPLAY_VER()
check from Gen 11 to Gen 9. Do it that way.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231103201831.1037416-16-andriy.shevchenko@linux.intel.com