bootstat: Adds additional reboot reason patterns

- Adding allowance for arbitrary ota subreason details, such as
  success or failure conditions
- Adding the new subreason "periodic", which is useful for POS devices
  which require e.g. daily reboots as part of security requirements
Test: Full Android build

Change-Id: Id0a6d38ed902e2b25fbb050980c763912c948f27
Signed-off-by: David Tracy <dtracy@squareup.com>

bootstat/bootstat.cpp

@@ -459,6 +459,8 @@ const std::map<std::string, int32_t> kBootReasonMap = {
     {"reboot,sys_ldo_ok,pmic,main", 227},
     {"reboot,sys_ldo_ok,pmic,sub", 228},
     {"reboot,smpl_timeout,pmic,main", 229},
+    {"reboot,ota,.*", 230},
+    {"reboot,periodic,.*", 231},
 };
 
 // Converts a string value representing the reason the system booted to an