chardev: use QEMUChrEvent instead of int

This uses the QEMUChrEvent enum everywhere except in IOEventHandler.
The IOEventHandler change needs to happen at once for all front ends and
is done with Coccinelle in the next patch.

(Extracted from a patch by Philippe Mathieu-Daudé).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

chardev/char-mux.c

@@ -117,7 +117,7 @@ static void mux_print_help(Chardev *chr)
     }
 }
 
-static void mux_chr_send_event(MuxChardev *d, int mux_nr, int event)
+static void mux_chr_send_event(MuxChardev *d, int mux_nr, QEMUChrEvent event)
 {
     CharBackend *be = d->backends[mux_nr];
 
@@ -126,7 +126,7 @@ static void mux_chr_send_event(MuxChardev *d, int mux_nr, int event)
     }
 }
 
-static void mux_chr_be_event(Chardev *chr, int event)
+static void mux_chr_be_event(Chardev *chr, QEMUChrEvent event)
 {
     MuxChardev *d = MUX_CHARDEV(chr);
 
@@ -232,7 +232,7 @@ static void mux_chr_read(void *opaque, const uint8_t *buf, int size)
         }
 }
 
-void mux_chr_send_all_event(Chardev *chr, int event)
+void mux_chr_send_all_event(Chardev *chr, QEMUChrEvent event)
 {
     MuxChardev *d = MUX_CHARDEV(chr);
     int i;