staging: slicoss: change some macros into inline functions

This patch changes macros into inline functions to avoid this checkpatch
check:
Macro argument 'x' may be better as '(x)' to avoid precedence issues

It also removes two macros because they aren't being used.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>