chardev: move headers to include/chardev

So they are all in one place. The following patch will move serial &
parallel declarations to the respective headers.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff --git a/qmp.c b/qmp.c
index 84638e2..7ee9bcf 100644
--- a/qmp.c
+++ b/qmp.c
@@ -21,7 +21,7 @@
 #include "qemu/config-file.h"
 #include "qemu/uuid.h"
 #include "qmp-commands.h"
-#include "sysemu/char.h"
+#include "chardev/char.h"
 #include "ui/qemu-spice.h"
 #include "ui/vnc.h"
 #include "sysemu/kvm.h"