Staging: unisys: visorchipset: Clean up sparse warnings in visorchipset code.

Clean up code to get rid of sparse warnings due to accessing I/O space.  Also
declared functions and variables as static if they are only used locally.

Signed-off-by: Ken Cox <jkc@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>