drm: unexport drm_global_mutex

Drivers really, really have no business even looking at this lock. And
thankfully they don't.

So unexport it and move the declaration to drm_internal.h.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_fops.c

@@ -43,7 +43,6 @@
 
 /* from BKL pushdown */
 DEFINE_MUTEX(drm_global_mutex);
-EXPORT_SYMBOL(drm_global_mutex);
 
 static int drm_open_helper(struct file *filp, struct drm_minor *minor);
 

drivers/gpu/drm/drm_internal.h

@@ -25,6 +25,7 @@
 extern unsigned int drm_timestamp_monotonic;
 
 /* drm_fops.c */
+extern struct mutex drm_global_mutex;
 int drm_lastclose(struct drm_device *dev);
 
 /* drm_pci.c */

drivers/gpu/drm/drm_lock.c

@@ -36,6 +36,7 @@
 #include <linux/export.h>
 #include <drm/drmP.h>
 #include "drm_legacy.h"
+#include "drm_internal.h"
 
 static int drm_notifier(void *priv);
 

include/drm/drmP.h

@@ -1087,7 +1087,6 @@ extern long drm_compat_ioctl(struct file *filp,
 extern bool drm_ioctl_flags(unsigned int nr, unsigned int *flags);
 
 				/* Device support (drm_fops.h) */
-extern struct mutex drm_global_mutex;
 extern int drm_open(struct inode *inode, struct file *filp);
 extern ssize_t drm_read(struct file *filp, char __user *buffer,
 			size_t count, loff_t *offset);