When asn1_encode_sequence() fails, WARN is not the correct solution.
1. asn1_encode_sequence() is not an internal function (located
in lib/asn1_encode.c).
2. Location is known, which makes the stack trace useless.
3. Results a crash if panic_on_warn is set.
It is also noteworthy that the use of WARN is undocumented, and it
should be avoided unless there is a carefully considered rationale to
use it.
Replace WARN with pr_err, and print the return value instead, which is
only useful piece of information.
Cc: stable@vger.kernel.org # v5.13+
Fixes: f221974525 ("security: keys: trusted: use ASN.1 TPM2 key format for the blobs")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
050bf3c793