tests: drivers: build_all: display: clean up reg addresses

Clean up register addresses for devices defined as children of the dummy
SPI bus, so that they start from zero. This ensures all SPI chip select
gpio indices will be used

(cherry picked from commit 1893928)

Original-Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
GitOrigin-RevId: 1893928
Change-Id: I21b98c7cc38f1d5f7a8484dd4011718314748214
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5635337
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Tested-by: Dawid Niedźwiecki <dawidn@google.com>
Reviewed-by: Dawid Niedźwiecki <dawidn@google.com>
Commit-Queue: Dawid Niedźwiecki <dawidn@google.com>

tests/drivers/build_all/display/app.overlay

@@ -153,19 +153,19 @@
  &test_gpio 0 3 &test_gpio 0 4 &test_gpio 0 5
  &test_gpio 0 6>;
 
- test_led_strip_0: lpd8806@2 {
+ test_led_strip_0: lpd8806@0 {
  compatible = "greeled,lpd8806";
- reg = <2>;
+ reg = <0>;
  spi-max-frequency = <2000000>;
  chain-length = <1>;
  color-mapping = <LED_COLOR_ID_RED
  LED_COLOR_ID_GREEN
  LED_COLOR_ID_BLUE>;
  };
 
- test_led_strip_1: ws2812_spi@3 {
+ test_led_strip_1: ws2812_spi@1 {
  compatible = "worldsemi,ws2812-spi";
- reg = <3>;
+ reg = <1>;
  spi-max-frequency = <2000000>;
  spi-one-frame = <1>;
  spi-zero-frame = <1>;