[virtualization][vmm] Minor code cleanup

Move definition of alloc_device_addr() next to the definition of
kFirstDynamicDeviceAddr that it uses.

Change-Id: Iaa803775a363cf288fbaab5b93623cd887e5b93d
diff --git a/src/virtualization/bin/vmm/main.cc b/src/virtualization/bin/vmm/main.cc
index a7d1e65..085e9066 100644
--- a/src/virtualization/bin/vmm/main.cc
+++ b/src/virtualization/bin/vmm/main.cc
@@ -72,6 +72,13 @@
 // allocator that starts fairly high in the guest physical address space.
 static constexpr zx_gpaddr_t kFirstDynamicDeviceAddr = 0xc00000000;
 
+static zx_gpaddr_t alloc_device_addr(size_t device_size) {
+  static zx_gpaddr_t next_device_addr = kFirstDynamicDeviceAddr;
+  zx_gpaddr_t ret = next_device_addr;
+  next_device_addr += device_size;
+  return ret;
+}
+
 static zx_status_t read_guest_cfg(const char* cfg_path, fuchsia::virtualization::GuestConfig* cfg) {
   std::string cfg_str;
   if (files::ReadFileToString(cfg_path, &cfg_str)) {
@@ -84,13 +91,6 @@
   return ZX_OK;
 }
 
-static zx_gpaddr_t alloc_device_addr(size_t device_size) {
-  static zx_gpaddr_t next_device_addr = kFirstDynamicDeviceAddr;
-  zx_gpaddr_t ret = next_device_addr;
-  next_device_addr += device_size;
-  return ret;
-}
-
 int main(int argc, char** argv) {
   syslog::InitLogger({"vmm"});