Revert "Wifi: Support NVT-ASCII in passphrase"

This reverts commit 8ba146cefb5bcb30c82228870ca1ee06b78d8743.

Reason for revert: Based on 802.11i specification,
this patch is not necessary.
Bug: 129974610
Test: Build pass. WiFi connection works.

Change-Id: I0046bb67bf2a3c1f265bc72f75e59ab1c43a4842
3 files changed