cpu: make CPU_INTERRUPT_RESET available on all targets

On the x86, some devices need access to the CPU reset pin (INIT#).
Provide a generic service to do this, using one of the internal
cpu_interrupt targets.  Generalize the PPC-specific code for
CPU_INTERRUPT_RESET to other targets.

Since PPC does not support migration across QEMU versions (its
machine types are not versioned yet), I picked the value that
is used on x86, CPU_INTERRUPT_TGT_INT_1.  Consequently, TGT_INT_2
and TGT_INT_3 are shifted down by one while keeping their value.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/cpu-exec.c b/cpu-exec.c
index 2f54054..38e5f02 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -336,19 +336,25 @@
                     }
 #endif
 #if defined(TARGET_I386)
+                    if (interrupt_request & CPU_INTERRUPT_INIT) {
+                        cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0);
+                        do_cpu_init(x86_cpu);
+                        cpu->exception_index = EXCP_HALTED;
+                        cpu_loop_exit(cpu);
+                    }
+#else
+                    if (interrupt_request & CPU_INTERRUPT_RESET) {
+                        cpu_reset(cpu);
+                    }
+#endif
+#if defined(TARGET_I386)
 #if !defined(CONFIG_USER_ONLY)
                     if (interrupt_request & CPU_INTERRUPT_POLL) {
                         cpu->interrupt_request &= ~CPU_INTERRUPT_POLL;
                         apic_poll_irq(x86_cpu->apic_state);
                     }
 #endif
-                    if (interrupt_request & CPU_INTERRUPT_INIT) {
-                            cpu_svm_check_intercept_param(env, SVM_EXIT_INIT,
-                                                          0);
-                            do_cpu_init(x86_cpu);
-                            cpu->exception_index = EXCP_HALTED;
-                            cpu_loop_exit(cpu);
-                    } else if (interrupt_request & CPU_INTERRUPT_SIPI) {
+                    if (interrupt_request & CPU_INTERRUPT_SIPI) {
                             do_cpu_sipi(x86_cpu);
                     } else if (env->hflags2 & HF2_GIF_MASK) {
                         if ((interrupt_request & CPU_INTERRUPT_SMI) &&
@@ -405,9 +411,6 @@
                         }
                     }
 #elif defined(TARGET_PPC)
-                    if ((interrupt_request & CPU_INTERRUPT_RESET)) {
-                        cpu_reset(cpu);
-                    }
                     if (interrupt_request & CPU_INTERRUPT_HARD) {
                         ppc_hw_interrupt(env);
                         if (env->pending_interrupts == 0) {