target-sh4: move intr_at_halt out of cpu_halted()

All targets except SH4 have the same cpu_halted() routine, and it has
only one caller. It is therefore a good candidate for inlining.

The difference is the handling of the intr_at_halt, which is necessary
to ignore SR.BL when sleeping. Move intr_at_halt handling out of it, by
setting this variable while executing the sleep instruction, and
clearing it when the CPU has been woken-up by an interrupt, whatever the
state of SR.BL. Also rename this variable in_sleep.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target-sh4/helper.c b/target-sh4/helper.c
index d2038bd..8f36d31 100644
--- a/target-sh4/helper.c
+++ b/target-sh4/helper.c
@@ -90,11 +90,11 @@
         if (do_exp && env->exception_index != 0x1e0) {
             env->exception_index = 0x000; /* masked exception -> reset */
         }
-        if (do_irq && !env->intr_at_halt) {
+        if (do_irq && !env->in_sleep) {
             return; /* masked */
         }
-        env->intr_at_halt = 0;
     }
+    env->in_sleep = 0;
 
     if (do_irq) {
         irq_vector = sh_intc_get_pending_vector(env->intc_handle,