staging: slicoss: improve implementation concerning the shared memory

Remove the volatile specifiers of struct slic_shmem. Furthermore store the
bus addresses for the isr pointer, link status and statistics separately
and access the upper and lower word of these addresses by means of
[lower|upper]_32_bits(). By doing this take the endianness into account.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>