platform: msm_shared: Add platform subtype for 8053 IOT platform

Add platform subtype to enable Platform specific conditional
logic in Bootloader code.

Change-Id: I28119eb7ba9980fdd7e17a01a70dcf10b2060ea3
diff --git a/platform/msm_shared/smem.h b/platform/msm_shared/smem.h
index 50193bd..e1b9082 100644
--- a/platform/msm_shared/smem.h
+++ b/platform/msm_shared/smem.h
@@ -491,6 +491,7 @@
 	HW_PLATFORM_SUBTYPE_8974PRO_PM8084 = 1,
 	HW_PLATFORM_SUBTYPE_CSFB = 1,
 	HW_PLATFORM_SUBTYPE_SVLTE1 = 2,
+	HW_PLATFORM_SUBTYPE_IOT = 2,
 	HW_PLATFORM_SUBTYPE_SVLTE2A = 3,
 	HW_PLATFORM_SUBTYPE_SGLTE = 6,
 	HW_PLATFORM_SUBTYPE_DSDA = 7,