init: Support reboot reason with thermal warmreset

Thermal shutdown could be due to tskin temperature or
battery temperature. Pass reason while rebooting the
system to reflect properly in boot.reason

Bug: 238464124
Test: Build and boot on device. Check reboot reason
for thermal shutdown and battery thermal shutdown with
thermal warmreset enabled.

Change-Id: I192562fed48ae7da7843e383362cd22a76ce479f
diff --git a/init/reboot_utils.h b/init/reboot_utils.h
index a0023b9..09e87ef 100644
--- a/init/reboot_utils.h
+++ b/init/reboot_utils.h
@@ -29,7 +29,8 @@
 // so if any of the attempts to determine this fail, it will still return true.
 bool IsRebootCapable();
 // This is a wrapper around the actual reboot calls.
-void __attribute__((noreturn)) RebootSystem(unsigned int cmd, const std::string& reboot_target);
+void __attribute__((noreturn)) RebootSystem(unsigned int cmd, const std::string& reboot_target,
+                                            const std::string& reboot_reason = "");
 void __attribute__((noreturn)) InitFatalReboot(int signal_number);
 void InstallRebootSignalHandlers();