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>

chardev/char-parallel.c

@@ -22,7 +22,7 @@
  * THE SOFTWARE.
  */
 #include "qemu/osdep.h"
-#include "sysemu/char.h"
+#include "chardev/char.h"
 #include "qapi/error.h"
 #include <sys/ioctl.h>
 
@@ -41,8 +41,8 @@
 #endif
 #endif
 
-#include "char-fd.h"
-#include "char-parallel.h"
+#include "chardev/char-fd.h"
+#include "chardev/char-parallel.h"
 
 #if defined(__linux__)