coreboot: Remove redundant file cache.c

File cache.c under armltd/armv8 is redundant as this file is already present
under src/arch/aarch64.

BUG=None
BRANCH=None
TEST=Compiled successfully

Change-Id: If5416c2d8cbb20cdd5a6ebd374250972719e5bc5
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/190364
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
2 files changed