platform: Define macros for the responded transferflags

`Table 16: PollForPlatformEventMessage command format` and `Table 68:
GetPDR command format` in DSP0248 v1.2.2 define the values of the
responded `transferflag` for PLDM platform and control commands.
Add the definition for further using.

Change-Id: Ibd97918a7a5add10dbb5db7c044c71daa5bbaa4e
Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dd6aa24..a5c3f90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@
 1. base: Define macros for reserved TIDs
 2. pdr: Add pldm_entity_association_pdr_add_contained_entity_to_remote_pdr()
 3. pdr: Add pldm_entity_association_pdr_create_new()
+4. platform: Define macros for the responded transferflags
 
 ### Deprecated
 
diff --git a/include/libpldm/platform.h b/include/libpldm/platform.h
index 1d34a7a..2384de3 100644
--- a/include/libpldm/platform.h
+++ b/include/libpldm/platform.h
@@ -13,6 +13,17 @@
 #include <libpldm/pdr.h>
 #include <libpldm/pldm_types.h>
 
+/**
+ * @brief PLDM response transfer flag for the Platform and control commands
+ *        (GetPDRs, PollForPlatformEventMessage)
+ */
+enum pldm_platform_transfer_flag {
+	PLDM_PLATFORM_TRANSFER_START = 0x00,
+	PLDM_PLATFORM_TRANSFER_MIDDLE = 0x01,
+	PLDM_PLATFORM_TRANSFER_END = 0x04,
+	PLDM_PLATFORM_TRANSFER_START_AND_END = 0x05,
+};
+
 /* Maximum size for request */
 #define PLDM_SET_STATE_EFFECTER_STATES_REQ_BYTES  19
 #define PLDM_GET_STATE_SENSOR_READINGS_REQ_BYTES  4