move QEMUSGList typedef

Move the QEMUSGList typedef to qemu-common so it can easily be used.
The actual struct definition stays in dma.h.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

dma.h

@@ -20,12 +20,12 @@ typedef struct {
     target_phys_addr_t len;
 } ScatterGatherEntry;
 
-typedef struct {
+struct QEMUSGList {
     ScatterGatherEntry *sg;
     int nsg;
     int nalloc;
     target_phys_addr_t size;
-} QEMUSGList;
+};
 
 void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint);
 void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,

qemu-common.h

@@ -270,6 +270,7 @@ typedef struct I2SCodec I2SCodec;
 typedef struct SSIBus SSIBus;
 typedef struct EventNotifier EventNotifier;
 typedef struct VirtIODevice VirtIODevice;
+typedef struct QEMUSGList QEMUSGList;
 
 typedef uint64_t pcibus_t;