apic: qdev conversion cleanup

Make APICState completely private to apic.c by using DeviceState
in external APIs.

Move apic_init() to pc.c.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/qemu-common.h b/qemu-common.h
index 00998c3..3fb2f0b 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -16,6 +16,7 @@
 typedef struct QEMUTimer QEMUTimer;
 typedef struct QEMUFile QEMUFile;
 typedef struct QEMUBH QEMUBH;
+typedef struct DeviceState DeviceState;
 
 /* Hack around the mess dyngen-exec.h causes: We need QEMU_NORETURN in files that
    cannot include the following headers without conflicts. This condition has
@@ -224,7 +225,6 @@
 typedef struct MouseTransformInfo MouseTransformInfo;
 typedef struct uWireSlave uWireSlave;
 typedef struct I2SCodec I2SCodec;
-typedef struct DeviceState DeviceState;
 typedef struct SSIBus SSIBus;
 typedef struct EventNotifier EventNotifier;
 typedef struct VirtIODevice VirtIODevice;