rename target_phy_addr_t to hwaddr to match upstream.

Upstream got rid of the target_phys_addr_t and replaced it with 'hwaddr',
so do the corresponding rename here. Note that:

- This also renames <exec/targphys.h> to <exec/hwaddr.h>

- Upstream always deins hwaddr as a 64-bit type, while the size of
  our own hwaddr is still controlled by TARGET_PHYS_ADDR_BITS, and
  will be 32 for now.

  A future patch will change the type definition to fully match
  upstream, but it is more risky / requires more cleanups. It's
  simply cleaner / simpler to put the related work in a separate
  patch, given the large number of sources touched by the
  current change.

Change-Id: Iee30869a57798c12109b6a23570b166232bb9244
diff --git a/dma-helpers.c b/dma-helpers.c
index 280ace4..29b3138 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -18,8 +18,8 @@
     qsg->size = 0;
 }
 
-void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
-                     target_phys_addr_t len)
+void qemu_sglist_add(QEMUSGList *qsg, hwaddr base,
+                     hwaddr len)
 {
     if (qsg->nsg == qsg->nalloc) {
         qsg->nalloc = 2 * qsg->nalloc + 1;
@@ -44,7 +44,7 @@
     uint64_t sector_num;
     int is_write;
     int sg_cur_index;
-    target_phys_addr_t sg_cur_byte;
+    hwaddr sg_cur_byte;
     QEMUIOVector iov;
     QEMUBH *bh;
 } DMAAIOCB;
@@ -82,7 +82,7 @@
 static void dma_bdrv_cb(void *opaque, int ret)
 {
     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
-    target_phys_addr_t cur_addr, cur_len;
+    hwaddr cur_addr, cur_len;
     void *mem;
 
     dbs->acb = NULL;