UPSTREAM: lib: dynamic_debug: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Bug: 145162121
Cc: linux-kernel@vger.kernel.org
Acked-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 9fd714cd7f4676e8ff3f840911a8d64cacbeab8b)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I471385f3af3f96c767f59ae76ea0a115c9eb4f7a