staging: dgap: remove unnecessary brackets

This patch removes unnecessary brackets when dealing with
unary operators like '&'.
Done with coccinelle semantic patch:

@@
expression e;
@@

(
- &(e)
+ &e
)

Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>