Combine Broadwell Chromeboxes using variant board scheme

Combine Broadwell Chromeboxes using variant board scheme

Combine existing boards google/guado, rikku, and tidus using
their common reference board google/jecht as a base.

Additional changes besides simple consolidation include:
 - simplify power LED functions
 - simplify HDA verb definitions using azelia macros
 - use common SoC functions to generate FADT table
 - correct FADT table header version
 - remove unused haswell_pci_irqs.asl
 - remove unused header includes (various)
 - set sane default fan speed (0x4d) for all variants

Variant setup modeled after google/beltino

Change-Id: I77a2dffe9601734916a33fd04ead98016ad0bc4b
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/17913
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>