ANDROID: Log which device failed to suspend in dpm_suspend_start()

Problem background: In the process of suspend, maybe some device suspend
callback failed in dpm_suspend_start()/dpm_prepare()/dpm_suspend().
Because it's after suspend_console(), so printf() is disabled now.
Currently we can see "Some devices failed to suspend, or early wake
event detected" by log_suspend_abort_reason() in bugreport. There are
many devices but we don't know which exactly device failed. So we
want to do a little change to record which device failed.

Note: I checked upstream LTS kernel, then I found the
patch can not be sent upstream, because it uses function
log_suspend_abort_reason() in wakeup_reason.c, the initial
patch(https://patchwork.kernel.org/patch/3827331/) for adding
/kernel/power/wakeup_reason.c is not accepted by upstream which
was merged in AOSP common kernels. So maybe the patch could
only be sent to AOSP common kernels.

Test: manual - Use modified version for daily use two days, from
bugreport we can see which device failed.
Bug: 120445600
Change-Id: I326c87ca1263496db79d08ec615f12fc22452d7a
Signed-off-by: zhuguangqing <[email protected]>

drivers/base/power/main.c

@@ -2007,6 +2007,7 @@ int dpm_prepare(pm_message_t state)
 			}
 			pr_info("Device %s not prepared for power transition: code %d\n",
 				dev_name(dev), error);
+			dpm_save_failed_dev(dev_name(dev));
 			put_device(dev);
 			break;
 		}