dcmi : implement get temperature readings

This commit implements the plumbing around the 'Get Temperature
Readings' command. It doesn't read the temperatures from the relevant
sensors. That code is coming up in a subsequent commit.

Change-Id: I4514b65eb3ca65d52dd35185338a2c397e9a76ca
Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
diff --git a/host-ipmid-whitelist.conf b/host-ipmid-whitelist.conf
index 941800a..f1084d0 100644
--- a/host-ipmid-whitelist.conf
+++ b/host-ipmid-whitelist.conf
@@ -30,3 +30,4 @@
 0x2C:0x01    //<Group Extension>:<Get DCMI Capabilities>
 0x2C:0x03    //<Group Extension>:<Get Power Limit>
 0x2C:0x06    //<Group Extension>:<Get Asset Tag>
+0x2C:0x10    //<Group Extension>:<Get Temperature Readings>