Let's not use the term blacklist in the function
serverworks_osb4_filter() documentation comment and rather simply refer
to what that function looks at: the list of devices with groken UDMA5.

While at it, also constify the values of the csb_bad_ata100 array.

Of note is that all of this should probably be handled using libata
quirk mechanism but it is unclear if these UDMA5 quirks are specific
to this controller only.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Igor Pylypiv <ipylypiv@google.com>