cpu: Replace do_interrupt() by CPUClass::do_interrupt method

This removes a global per-target function and thus takes us one step
closer to compiling multiple targets into one executable.

It will also allow to override the interrupt handling for certain CPU
families.

Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/target-openrisc/interrupt.c b/target-openrisc/interrupt.c
index 7f2c025..16ef4b3 100644
--- a/target-openrisc/interrupt.c
+++ b/target-openrisc/interrupt.c
@@ -25,8 +25,10 @@
 #include "hw/loader.h"
 #endif
 
-void do_interrupt(CPUOpenRISCState *env)
+void openrisc_cpu_do_interrupt(CPUState *cs)
 {
+    OpenRISCCPU *cpu = OPENRISC_CPU(cs);
+    CPUOpenRISCState *env = &cpu->env;
 #ifndef CONFIG_USER_ONLY
     if (env->flags & D_FLAG) { /* Delay Slot insn */
         env->flags &= ~D_FLAG;