lib/vpd: Remove vpd_file_cache

Strago was the last board to require this feature.

BUG=b:77594752
TEST=cros_workon_make --board=ghost --test mosys

Cq-Depend: chromium:3832398
Change-Id: I2b746b37e07b51b90a0c5dd50b71c91de99181d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/3829777
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
5 files changed