guiconfig search fails

[mbolivar-nordic]

Describe the bug

The guiconfig module has an unused import.

To Reproduce
Steps to reproduce the behavior:

1. west build -t guiconfig
2. control-f
3. type some search term and hit enter

Get this:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/home/mbolivar/zp/zephyr/scripts/kconfig/guiconfig.py", line 1865, in _update_jump_to_matches
    regex_searches = [re.compile(regex).search
  File "/home/mbolivar/zp/zephyr/scripts/kconfig/guiconfig.py", line 1865, in <listcomp>
    regex_searches = [re.compile(regex).search
NameError: name 're' is not defined

Expected behavior

Search results

Impact

High impact to guiconfig