ibexpeak / bd82x6x: Make SATA mode user-visible option.

Ability to choose compatibility mode is interesting for testing payloads and
OS for compatibility with older systems.

As per comments
"ide_legacy_combined # TODO: Does nothing since
		      generations, remove from sb code?"
The "combined" mode was removed. It wasn't used by any mobo and the code for
it is almost identical to IDE one other than few bits relating to interrupt
handling and ISA mode.

Change-Id: I407a8fac753b513812a86bef5abcf39c6d81472e
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/4658
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
24 files changed