regulator: Fix error checking for debugfs_create_dir

stable inclusion
from stable-v5.10.185
commit dbf610997242ec62facd04a11c5258ba84607ea1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8L5XP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dbf610997242ec62facd04a11c5258ba84607ea1



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[ Upstream commit 2bf1c45b ]

This patch fixes the error checking in core.c in debugfs_create_dir.
The correct way to check if an error occurred is 'IS_ERR' inline function.

Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
Suggested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230515172938.13338-1-osmtendev@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>