accel: Expose and register generic_handle_interrupt()

In order to dispatch over AccelOpsClass::handle_interrupt(),
we need it always defined, not calling a hidden handler under
the hood. Make AccelOpsClass::handle_interrupt() mandatory.
Expose generic_handle_interrupt() prototype and register it
for each accelerator.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Mads Ynddal <mads@ynddal.dk>
Message-Id: <20250703173248.44995-29-philmd@linaro.org>

include/system/accel-ops.h

@@ -62,6 +62,7 @@ struct AccelOpsClass {
     void (*synchronize_pre_loadvm)(CPUState *cpu);
     void (*synchronize_pre_resume)(bool step_pending);
 
+    /* handle_interrupt is mandatory. */
     void (*handle_interrupt)(CPUState *cpu, int mask);
 
     /**
@@ -86,4 +87,6 @@ struct AccelOpsClass {
     void (*remove_all_breakpoints)(CPUState *cpu);
 };
 
+void generic_handle_interrupt(CPUState *cpu, int mask);
+
 #endif /* ACCEL_OPS_H */