staging: unisys: Rework Kconfig dependencies

I find the Kconfig dependencies of the various Unisys drivers rather
confusing. Due to the dependencies, you must select the drivers one by
one to see the following ones. So if you are looking for a specific
driver, it is not visible by default. And if you don't know exactly
what you need, it's even worse as you don't know what is available.

In a case like this with several helper drivers and many dependencies,
I think it makes more sense to list all the drivers at first, and use
select statements to fulfill the dependencies for the user.

As a nice side effect, it avoids the weird indentation, which was
technically correct but still somewhat confusing.

I also dropped the dependencies on HAS_IOMEM, as the whole driver set
is for X86_64 only anyway which always has HAS_IOMEM set. And I
dropped the redundant dependencies on UNISYSSPAR as all drivers are
already inside an "if UNISYSSPAR" block.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Benjamin Romer <benjamin.romer@unisys.com>
Cc: David Kershner <david.kershner@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>