gpu: host1x: Clean up debugfs in error handling path

host1x_debug_init() must be reverted in an error handling path.

This is already fixed in the remove function since commit 44156eee
("gpu: host1x: Clean up debugfs on removal")

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Thierry Reding <treding@nvidia.com>