hw/char/escc: convert Sun mouse to use QemuInputHandler

hw/char/escc: convert Sun mouse to use QemuInputHandler

Update the Sun mouse implementation to use QemuInputHandler instead of the
legacy qemu_add_mouse_event_handler() function.

Note that this conversion adds extra sunmouse_* members to ESCCChannelState
but they are not added to the migration stream (similar to the Sun keyboard
members). If this were desired in future, the Sun devices should be split
into separate devices and added to the migration stream there instead.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2518
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Carl Hauser <chauser@pullman.com>
Message-ID: <20240904102301.175706-1-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>