util: Include stdint.h in libdrm.h

drmGetDevices2()'s first parameter is a uint32_t.

Fixes: e05abb1345 ("util: Add a simple no-op libdrm shim")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26265>
(cherry picked from commit 5022a26b50)

.pick_status.json

@@ -14,7 +14,7 @@
         "description": "util: Include stdint.h in libdrm.h",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "e05abb1345530433681e2a4965588e4e2f51380b",
         "notes": null

src/util/libdrm.h

@@ -32,6 +32,7 @@
 #else
 
 #include <errno.h>
+#include <stdint.h>
 
 #define DRM_NODE_PRIMARY 0
 #define DRM_NODE_CONTROL 1