staging: sm750fb: Removed unnecessary parentheses.

Removed parentheses on the right hand side of assignment, as they are
not required. The following coccinelle script was used to fix this
issue:

@@
local idexpression id;
expression e;
@@

id =
-(
e
-)

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>