btrfs: fix trace event name typo for FLUSH_DELAYED_REFS

stable inclusion
from stable-v5.10.165
commit 2cbd815970f82af428c9201db82a57835236ad30
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7T7G4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2cbd815970f82af428c9201db82a57835236ad30



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[ Upstream commit 0a3212de ]

Fix a typo of printing FLUSH_DELAYED_REFS event in flush_space() as
FLUSH_ELAYED_REFS.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>