broadwell: Change CPUID 306D4 to report "E0 or F0"

broadwell: Change CPUID 306D4 to report "E0 or F0"

The F0 stepping has the same CPUID as E0 stepping so report
it as either stepping to avoid confusion.

BUG=chrome-os-partner:32359
BRANCH=samus,auron
TEST=build and boot on samus

Change-Id: I99a83855b4393d736724836b709702417483b5d2
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: 55ed3bc880c31c0ca5c8a21c335722af05eb57f7
Original-Change-Id: Ia4955f346ceb9be92e06ecea5b7a8fe2db84cabc
Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/223097
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9226
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>