Drop unnecessary CONFIG_ prefixes.

The scripts/config command doesn't need you to specify the prefix, and
in my testing, it'll actually duplicate it. I'm not sure how this has
been working, but it's definitely wrong. Remove the CONFIG_ prefixes.

Bug: 79546208
Change-Id: I27abde2e86a9b4c0fe12a6472a7c1032f7b53b7b
Signed-off-by: Alistair Strachan <astrachan@google.com>