drm/i915: Call i915_globals_exit() if pci_register_device() fails

In the unlikely event that pci_register_device() fails, we were tearing
down our PMU setup but not globals.  This leaves a bunch of memory slabs
lying around.
Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Fixes: 32eb6bcf ("drm/i915: Make request allocation caches global")
[danvet: Fix conflicts against removal of the globals_flush
infrastructure.]
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721152358.2893314-3-jason@jlekstrand.net
(cherry picked from commit db484889)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Fixed small conflict while cherry picking]

drivers/gpu/drm/i915/i915_globals.c

@@ -148,7 +148,7 @@ static void __exit __i915_globals_flush(void)
 	atomic_dec(&active);
 }
 
-void __exit i915_globals_exit(void)
+void i915_globals_exit(void)
 {
 	GEM_BUG_ON(atomic_read(&active));
 

drivers/gpu/drm/i915/i915_pci.c

@@ -1195,6 +1195,7 @@ static int __init i915_init(void)
 	err = pci_register_driver(&i915_pci_driver);
 	if (err) {
 		i915_pmu_exit();
+		i915_globals_exit();
 		return err;
 	}