hv:fix "no prototype for non-static function"

change some APIs to static or include header file

Tracked-On: #861
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>

hypervisor/common/hypercall.c

@@ -15,6 +15,7 @@
 #include <assign.h>
 #include <ept.h>
 #include <mmu.h>
+#include <hypercall.h>
 #include <errno.h>
 #include <logmsg.h>
 

hypervisor/common/trusty_hypercall.c

@@ -5,6 +5,7 @@
  */
 
 #include <vm.h>
+#include <hypercall.h>
 #include <errno.h>
 #include <logmsg.h>