memory: drop find_ram_block()

On the one hand, we have already qemu_get_ram_block() whose function
is similar. On the other hand, we can directly use mr->ram_block but
searching RAMblock by ram_addr which is a kind of waste.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <1462845901-89716-2-git-send-email-arei.gonglei@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/memory.c b/memory.c
index a8ef852..9daac5e 100644
--- a/memory.c
+++ b/memory.c
@@ -1673,7 +1673,7 @@
 {
     assert(mr->ram_block);
 
-    qemu_ram_resize(memory_region_get_ram_addr(mr), newsize, errp);
+    qemu_ram_resize(mr->ram_block, newsize, errp);
 }
 
 static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpace *as)