pm: re-program timer HW only when the exit latency is not zero

Avoid re-programming timer unnecessarily.

(cherry picked from commit 6a962fb)

Original-Signed-off-by: Dong Wang <[email protected]>
Original-Signed-off-by: Flavio Ceolin <[email protected]>
GitOrigin-RevId: 6a962fb
Change-Id: I1c2efbc0109b94015e63531ccaf2b3967c7c2d38
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5520822
Reviewed-by: Ting Shen <[email protected]>
Tested-by: ChromeOS Prod (Robot) <[email protected]>
Commit-Queue: Ting Shen <[email protected]>
Tested-by: Ting Shen <[email protected]>

Author: kwd-doodling

subsys/pm/pm.c

@@ -210,7 +210,8 @@ bool pm_system_suspend(int32_t ticks)
 	}
 #endif
 
-	if (ticks != K_TICKS_FOREVER) {
+	if ((z_cpus_pm_state[id].exit_latency_us != 0) &&
+	    (ticks != K_TICKS_FOREVER)) {
 		/*
 		 * We need to set the timer to interrupt a little bit early to
 		 * accommodate the time required by the CPU to fully wake up.