host-ipmid: ipmid-api: drop extern C linking

Header not used by any C code at this point, drop extern C linking and
unused headers associated with C compilation.

Change-Id: Icdb1dd220d158256562a2529d9aa7b03ed1e2196
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/host-ipmid/ipmid-api.h b/host-ipmid/ipmid-api.h
index e77e720..b9950b2 100644
--- a/host-ipmid/ipmid-api.h
+++ b/host-ipmid/ipmid-api.h
@@ -1,12 +1,7 @@
 #ifndef __HOST_IPMID_IPMI_COMMON_H__
 #define __HOST_IPMID_IPMI_COMMON_H__
-#include <stdbool.h>
-#include <stdlib.h>
-#include <systemd/sd-bus.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+#include <systemd/sd-bus.h>
 
 /*
  * Specifies the minimum privilege level required to execute the command
@@ -136,8 +131,4 @@
 sd_event* ipmid_get_sd_event_connection(void);
 sd_bus_slot* ipmid_get_sd_bus_slot(void);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif