mainboard: Strip out some dead includes

Change-Id: I0079fa089ba863c6e447bcee3440a7e0ba0f2372
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7429
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
Tested-by: build bot (Jenkins)
10 files changed