drm/xe: Fix build with CONFIG_MODULES=n

When building with CONFIG_MODULES=n, the __exit functions are dropped.
However our init functions may call them for error handling, so they are
not good candidates for the exit sections.

Fix this error reported by 0day:

	ld.lld: error: relocation refers to a symbol in a discarded section: xe_configfs_exit
	>>> defined in vmlinux.a(drivers/gpu/drm/xe/xe_configfs.o)
	>>> referenced by xe_module.c
	>>>               drivers/gpu/drm/xe/xe_module.o:(init_funcs) in archive vmlinux.a

This is the only exit function using __exit. Drop it to fix the build.

Cc: Riana Tauro <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Fixes: 16280de ("drm/xe: Add configfs to enable survivability mode")
Reviewed-by: Balasubramani Vivekanandan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lucas De Marchi <[email protected]>
(cherry picked from commit d9b2623)
Signed-off-by: Rodrigo Vivi <[email protected]>

Author: Lucas De Marchi

drivers/gpu/drm/xe/xe_configfs.c

@@ -404,7 +404,7 @@ int __init xe_configfs_init(void)
 	return 0;
 }
 
-void __exit xe_configfs_exit(void)
+void xe_configfs_exit(void)
 {
 	configfs_unregister_subsystem(&xe_configfs);
 }