staging: ozwpan: remove extra parentheses around left bit shift operations

Removes extra parentheses around bitwise left shift operations.
The case handled is when resultant value is assigned to a variable.
The issue was detected and resolved using the following
coccinelle script:

@@
expression e, e1;
constant c;
@@

e =
-(e1
+e1
<<
-c);
+c;

@@
identifier i;
constant c;
type t;
expression e;
@@

t i =
-(e
+e
<<
-c);
+c;

Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>