chardev: Restrict msmouse / wctablet / testdev to system emulation

The msmouse / wctablet / testdev character devices are only
used by system emulation. Remove them from user mode and tools.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200423202112.644-4-philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

chardev/Makefile.objs

@@ -17,7 +17,7 @@ chardev-obj-y += char-udp.o
 chardev-obj-$(CONFIG_WIN32) += char-win.o
 chardev-obj-$(CONFIG_WIN32) += char-win-stdio.o
 
-common-obj-y += msmouse.o wctablet.o testdev.o
+common-obj-$(CONFIG_SOFTMMU) += msmouse.o wctablet.o testdev.o
 
 ifeq ($(CONFIG_BRLAPI),y)
 common-obj-m += baum.o