ipmi: Add the i2c-addr property for SSIF interfaces

This is required for SSIF to work.

There was no way to know if the interface being added was SI
or SSIF from the platform data, but that was required so the
i2c-addr is only added for SSIF interfaces.  So add a field
for that.

Also rework the logic a bit so that ipmi-type is not set
for SSIF interfaces, as it is not necessary for that.

Fixes: 3cd83bac ("ipmi: Consolidate the adding of platform devices")
Reported-by: Kamlakant Patel <kamlakantp@marvell.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 5.1