boards: arduino: Giga Display Shield, touch points

Currently the config option:
CONFIG_INPUT_GT911_MAX_TOUCH_POINTS

is not defined for the Giga display shield and defaults
to 1.   The valid range is 1-5, I have done most of my
own testing using 3 with the ArduinoGiga-zephyr

I have a PR against the ArduinoCore-zephyr project
which allows me to define a callback in the Arduino

And a version of the Arduino touch library with some
support, the fork/branch

And an example sketch that does touch paint.

for gestures

(cherry picked from commit 52d1e2f)

Original-system:
Original-https: //github.com/arduino/ArduinoCore-zephyr/pull/134
Original-https: //github.com/KurtE/Arduino_GigaDisplayTouch/tree/zephyr
Original-https: //github.com/arduino/ArduinoCore-zephyr/issues/92#issuecomment-2944385198
Original-Note: my version of the Arduino touch library has no support
Original-Signed-off-by: Kurt Eckhardt <kurte@rockisland.com>
GitOrigin-RevId: 52d1e2f
Cr-Build-Id: 8710912179129064817
Cr-Build-Url: https://cr-buildbucket.appspot.com/build/8710912179129064817
Copybot-Job-Name: zephyr-main-copybot-downstream
Change-Id: Ib3be976f441e4003dac08449655333845ccc7f4b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/6683777
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: Keith Short <keithshort@chromium.org>
Tested-by: ChromeOS Copybot <copybot@chops-service-accounts.iam.gserviceaccount.com>

Author: Kurt Eckhardt

boards/shields/arduino_giga_display_shield/boards/arduino_giga_r1_m7.conf

@@ -6,3 +6,4 @@ CONFIG_STM32_LTDC_RGB565=y
 CONFIG_DISPLAY_INIT_PRIORITY=87
 CONFIG_STM32_LTDC_DISABLE_FMC_BANK1=y
 CONFIG_INPUT_GT911_INTERRUPT=y
+CONFIG_INPUT_GT911_MAX_TOUCH_POINTS=5