LinuxKPI: fix bug in le32p_replace_bits()

Fix a bug that slipped in in 90707c4e44de03ea36be183ef2226601c66169cb
using the correct field in le32p_replace_bits().

Sponsored by: The FreeBSD Foundation

(cherry picked from commit 22e20d852ff400a486da24e5d1d92c841a3e39d9)