NetFn: Use api.hpp instead of api.h

Since NetFn declared in api.h has been gradually deprecated, this
submission is to use api.hpp instead of api.h

Change-Id: I7631e68bd62d15dfc7274058b2ece38e3421a661
Signed-off-by: George Liu <liuxiwei@ieisystem.com>
diff --git a/ipmid-new.cpp b/ipmid-new.cpp
index 7d3dd2d..0b3e389 100644
--- a/ipmid-new.cpp
+++ b/ipmid-new.cpp
@@ -725,7 +725,7 @@
     // The original ipmi_register_callback allowed for group OEM handlers
     // to be registered via this same interface. It just so happened that
     // all the handlers were part of the DCMI group, so default to that.
-    if (netFn == NETFUN_GRPEXT)
+    if (netFn == ipmi::netFnGroup)
     {
         ipmi::impl::registerGroupHandler(ipmi::prioOpenBmcBase, ipmi::groupDCMI,
                                          cmd, realPriv, h);