[mutter] cogl: Mark _cogl_buffer_access_to_gl_enum static

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 99043e2af23ec3cab66c1c24680f1dfc8003a269
Author: Adam Jackson <ajax redhat com>
Date:   Tue Jan 21 13:56:04 2020 -0500

    cogl: Mark _cogl_buffer_access_to_gl_enum static
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/1015

 cogl/cogl/cogl-buffer-private.h      | 3 ---
 cogl/cogl/driver/gl/cogl-buffer-gl.c | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)
---
diff --git a/cogl/cogl/cogl-buffer-private.h b/cogl/cogl/cogl-buffer-private.h
index 00bc06c76..5ad556f6b 100644
--- a/cogl/cogl/cogl-buffer-private.h
+++ b/cogl/cogl/cogl-buffer-private.h
@@ -139,9 +139,6 @@ _cogl_buffer_fini (CoglBuffer *buffer);
 CoglBufferUsageHint
 _cogl_buffer_get_usage_hint (CoglBuffer *buffer);
 
-GLenum
-_cogl_buffer_access_to_gl_enum (CoglBufferAccess access);
-
 CoglBuffer *
 _cogl_buffer_immutable_ref (CoglBuffer *buffer);
 
diff --git a/cogl/cogl/driver/gl/cogl-buffer-gl.c b/cogl/cogl/driver/gl/cogl-buffer-gl.c
index b2119d7b0..7fce18a56 100644
--- a/cogl/cogl/driver/gl/cogl-buffer-gl.c
+++ b/cogl/cogl/driver/gl/cogl-buffer-gl.c
@@ -160,7 +160,7 @@ recreate_store (CoglBuffer *buffer,
   return TRUE;
 }
 
-GLenum
+static GLenum
 _cogl_buffer_access_to_gl_enum (CoglBufferAccess access)
 {
   if ((access & COGL_BUFFER_ACCESS_READ_WRITE) == COGL_BUFFER_ACCESS_READ_WRITE)