recovery: report compliant reboot reason (Part Deux)

shutdown and reboot should have a corresponding sub-reason.

Adding:
    "reboot,userrequested,fastboot"
    "reboot,userrequested,recovery"
    "reboot,userrequested,recovery,ui"
    "shutdown,userrequested,fastboot"
    "shutdown,userrequested,recovery"
    "reboot,unknown#" (Can't happen, debug)

Test: manual, multiple targets, enter recovery, be able to exit recovery
Bug: 133326470
Change-Id: Ibfcb2a23158e8e99922e8053edd815fb592150f2
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 14f5e4b..2023349 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -30,10 +30,10 @@
 #include "recovery_ui/ui.h"
 
 static const std::vector<std::pair<std::string, Device::BuiltinAction>> kFastbootMenuActions{
-  { "Reboot system now", Device::REBOOT },
+  { "Reboot system now", Device::REBOOT_FROM_FASTBOOT },
   { "Enter recovery", Device::ENTER_RECOVERY },
   { "Reboot to bootloader", Device::REBOOT_BOOTLOADER },
-  { "Power off", Device::SHUTDOWN },
+  { "Power off", Device::SHUTDOWN_FROM_FASTBOOT },
 };
 
 Device::BuiltinAction StartFastboot(Device* device, const std::vector<std::string>& /* args */) {