intel/e7501: Remove unused northbridge code

No boards left in the tree for this northbridge.

Change-Id: Id45da11b9d78cbd6bd50acb5a3c6c3c270f9020e
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17281
Tested-by: build bot (Jenkins)
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
8 files changed