vulkan: Portable wsi_common_get_current_time()

Use os_time_get_nano(), which has a Windows implementation.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7783>

src/vulkan/wsi/wsi_common.c

@@ -24,11 +24,11 @@
 #include "wsi_common_private.h"
 #include "util/macros.h"
 #include "util/os_file.h"
+#include "util/os_time.h"
 #include "util/xmlconfig.h"
 #include "vk_util.h"
 
 #include <time.h>
-#include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
 
@@ -671,7 +671,5 @@ wsi_common_queue_present(const struct wsi_device *wsi,
 uint64_t
 wsi_common_get_current_time(void)
 {
-   struct timespec current;
-   clock_gettime(CLOCK_MONOTONIC, &current);
-   return current.tv_nsec + current.tv_sec * 1000000000ull;
+   return os_time_get_nano();
 }