proto_tree_add_uint() takes a value, not an encoding, as an argument.

Change-Id: Ie2c0523e32b54cd13506501d98215934a8d1304e
Reviewed-on: https://code.wireshark.org/review/2611
Reviewed-by: Guy Harris <guy@alum.mit.edu>
(cherry picked from commit 4f1d20abae2c485bf0cdcaee10a917e4e01ebda1)
Reviewed-on: https://code.wireshark.org/review/2858