trace: ipc_logging: Release the debugfs SRCU when reading

Global debugfs SRCU lock is acquired while reading log_cont file
and not released until read operation is killed which blocks all
other clients adding and removing debugfs nodes.

Avoid using debugfs global SRCU lock during read operation by using
"debugfs_create_file_unsafe".

CRs-Fixed: 2066241
Change-Id: Ie471ca8f65123f1fd6db80d2006843d1a2250984
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>