m68k: add an interrupt controller

A (generic) copy of the GLUE device we already have for q800 to use with
the m68k-virt machine.
The q800 one would disappear in the future as q800 uses actually the djMEMC
controller.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210312214145.2936082-4-laurent@vivier.eu>
diff --git a/hw/intc/Kconfig b/hw/intc/Kconfig
index 186cb5d..f469408 100644
--- a/hw/intc/Kconfig
+++ b/hw/intc/Kconfig
@@ -70,3 +70,6 @@
 
 config GOLDFISH_PIC
     bool
+
+config M68K_IRQC
+    bool