pbzip2: Fix license warning

After below commit introduced, the LICENSE
field changed from BSD-4-Clause to bzip-1.0.6.
669600ef bzip2/pbzip2: Correct license information

But actually it should be bzip2-1.0.6,
update it to fix the below license warning:
WARNING: pbzip2-native-1.1.13-r0 do_populate_lic: pbzip2-native: No generic license file exists for: bzip-1.0.6 in any provider

Signed-off-by: Mingli Yu <mingli.yu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>