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-sh4/helper.c b/target-sh4/helper.c
index fd4efee..0a9cb3a 100644
--- a/target-sh4/helper.c
+++ b/target-sh4/helper.c
@@ -31,9 +31,12 @@
 
 #if defined(CONFIG_USER_ONLY)
 
-void do_interrupt (CPUSH4State *env)
+void superh_cpu_do_interrupt(CPUState *cs)
 {
-  env->exception_index = -1;
+    SuperHCPU *cpu = SUPERH_CPU(cs);
+    CPUSH4State *env = &cpu->env;
+
+    env->exception_index = -1;
 }
 
 int cpu_sh4_handle_mmu_fault(CPUSH4State * env, target_ulong address, int rw,
@@ -78,9 +81,10 @@
 #define MMU_DADDR_ERROR_READ     (-12)
 #define MMU_DADDR_ERROR_WRITE    (-13)
 
-void do_interrupt(CPUSH4State *env)
+void superh_cpu_do_interrupt(CPUState *cs)
 {
-    CPUState *cs = CPU(sh_env_get_cpu(env));
+    SuperHCPU *cpu = SUPERH_CPU(cs);
+    CPUSH4State *env = &cpu->env;
     int do_irq = cs->interrupt_request & CPU_INTERRUPT_HARD;
     int do_exp, irq_vector = env->exception_index;