platform: msm_shared: Fix reboot module

Fix reboot module to write reboot reason to PON register instead imem
cookie when PON registers usage is enabled, use REG_READ/REG_WRITE
macros for pmic-spmi read & writes, add shutdown_device API, use pmic
reboot APIs from target as the pmic reboot code changes based on the
pmic used for the target and remove unwanted header file inclusion.
Move the compilation of rpmb to the to end of the rules.mk otherwise
all the files below would be considered as part of rpmb module and
results in compilation error

Change-Id: I7ed4b213f42b1e3e49dd7b9b7fa56d37fd7db03e
diff --git a/platform/msm_shared/reboot.h b/platform/msm_shared/reboot.h
index 7156c01..c87f9d8 100644
--- a/platform/msm_shared/reboot.h
+++ b/platform/msm_shared/reboot.h
@@ -29,6 +29,7 @@
 #define FASTBOOT_MODE     0x77665500
 #define RECOVERY_MODE     0x77665502
 #define ALARM_BOOT        0x77665503
+
 #define RTC_TRG           4
 #define PON_SOFT_RB_SPARE 0x88F
 
@@ -44,3 +45,4 @@
 uint32_t check_alarm_boot(void);
 
 void reboot_device(unsigned reboot_reason);
+void shutdown_device();