Revert "samples: counter: alarm: remove platform_allow filterring"

this sample needs add dts defines for each platform, so should not be
generally enabled.

fixes: #90714

This reverts commit 022962c.

Signed-off-by: Hake Huang <[email protected]>

Author: hakehuang

samples/drivers/counter/alarm/sample.yaml

@@ -16,8 +16,32 @@ common:
   depends_on: counter
 tests:
   sample.drivers.counter.alarm:
-    platform_exclude:
-      - mps2/an385
+    platform_allow:
+      - nucleo_f746zg
+      - nrf51dk/nrf51822
+      - nrf52dk/nrf52832
+      - nrf52840dk/nrf52840
+      - nrf9160dk/nrf9160
+      - samd20_xpro
+      - bl5340_dvk/nrf5340/cpuapp
+      - gd32e103v_eval
+      - gd32e507z_eval
+      - gd32f403z_eval
+      - gd32f450i_eval
+      - gd32f450z_eval
+      - gd32e507v_start
+      - gd32f407v_start
+      - gd32f450v_start
+      - gd32f470i_eval
+      - stm32h735g_disco
+      - stm32h573i_dk
+      - rpi_pico
+      - mr_canhubk3
+      - s32z2xxdc2/s32z270/rtu0
+      - s32z2xxdc2/s32z270/rtu1
+      - s32z2xxdc2@D/s32z270/rtu0
+      - s32z2xxdc2@D/s32z270/rtu1
+      - lp_em_cc2340r5
     integration_platforms:
       - nucleo_f746zg
   sample.drivers.counter.alarm.stm32_rtc: