vga(4): fix vga_doswitch() declaration

[Scott Cheloha]

Timeout callback functions should be void (*)(void *).  I'd rather not
cast in order to shove the function pointer into timeout_set(9).

ok?

Index: vga.c
===================================================================
RCS file: /cvs/src/sys/dev/ic/vga.c,v
retrieving revision 1.73
diff -u -p -r1.73 vga.c
--- vga.c       25 May 2020 09:55:48 -0000      1.73
+++ vga.c       25 May 2021 18:38:59 -0000
@@ -254,7 +254,7 @@ void        vga_scrollback(void *, void *, int)
 void   vga_burner(void *v, u_int on, u_int flags);
 int    vga_getchar(void *, int, int, struct wsdisplay_charcell *);
 
-void vga_doswitch(struct vga_config *);
+void vga_doswitch(void *);
 
 const struct wsdisplay_accessops vga_accessops = {
        .ioctl = vga_ioctl,
@@ -763,8 +763,7 @@ vga_show_screen(void *v, void *cookie, i
        vc->switchcb = cb;
        vc->switchcbarg = cbarg;
        if (cb) {
-               timeout_set(&vc->vc_switch_timeout,
-                   (void(*)(void *))vga_doswitch, vc);
+               timeout_set(&vc->vc_switch_timeout, vga_doswitch, vc);
                timeout_add(&vc->vc_switch_timeout, 0);
                return (EAGAIN);
        }
@@ -774,8 +773,9 @@ vga_show_screen(void *v, void *cookie, i
 }
 
 void
-vga_doswitch(struct vga_config *vc)
+vga_doswitch(void *arg)
 {
+       struct vga_config *vc = arg;
        struct vgascreen *scr, *oldscr;
        struct vga_handle *vh = &vc->hdl;
        const struct wsscreen_descr *type;