Do encoding-arg changes (all benign)

For:
- FT_BYTES: Always use just ENC_NA
- integral/floating (other than FT_[U]INT8): Do ENC_NA --> ENC_BIG_ENDIAN

Also:
- FT_UINT... --> FT_UINT8 in a few cases (to match proto_tree_add_item...)
- Change one case of incorrect '||' to '|'

Change-Id: I427e0e61618ff8faf55691c8a695930f67d455b0
Reviewed-on: https://code.wireshark.org/review/4184
Reviewed-by: Bill Meier <wmeier@newsguy.com>