Print wIndex in decimal and hex

wIndex often contains different fields in it's upper & lower byte.
Printing in hex makes these seperate fields easier to read.

Change-Id: I69fb7e14b4f5b5a1ecd61bcae34f6d100f1a94b6
Reviewed-on: https://code.wireshark.org/review/2961
Reviewed-by: Anders Broman <a.broman58@gmail.com>