staging: slicoss: remove unused members of struct adapter

This patch removes two fields from the private "struct adapter".
Specifically,

memorybase      duplicate of slic_regs

memorylength    written once and never read. This field is trivially
                computed with pci_resource_len if it's ever needed in
                the future.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>