examples/fips_validation: fix string token for CT length
examples/fips_validation: fix string token for CT length

The NIST test vectors use the string 'PTlen' to denote text lengths
in case of encrypt & decrypt operations. So the same string needs to be
used while parsing PT and CT.

Fixes: 2adb3b4e7e54 ("examples/fips_validation: fix AES-GCM cipher length parsing")

Signed-off-by: Anoob Joseph <3ccb4777bd2856f4d9127f25efe6455b1a791ba2@marvell.com>
Acked-by: Akhil Goyal <74d7c4c993a22c1d4f60c46ff3d95c969a24a25c@nxp.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk