Allow various header files to be included from non-CPU code

Allow balloon.h, gdbstub.h and kvm.h to be included from
non-CPU code.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/kvm.h b/kvm.h
index fd8d0c1..4f77188 100644
--- a/kvm.h
+++ b/kvm.h
@@ -14,12 +14,12 @@
 #ifndef QEMU_KVM_H
 #define QEMU_KVM_H
 
-#include "config.h"
+#include "config-host.h"
 #include "qemu-queue.h"
 
-#ifdef CONFIG_KVM
 extern int kvm_allowed;
 
+#ifdef CONFIG_KVM
 #define kvm_enabled() (kvm_allowed)
 #else
 #define kvm_enabled() (0)
@@ -31,6 +31,7 @@
 
 int kvm_init(int smp_cpus);
 
+#ifdef NEED_CPU_H
 int kvm_init_vcpu(CPUState *env);
 
 int kvm_cpu_exec(CPUState *env);
@@ -160,5 +161,5 @@
         kvm_cpu_synchronize_post_init(env);
     }
 }
-
+#endif
 #endif