staging: xgifb: Remove unneeded parentheses

Remove unneeded parentheses around the right hand side of assignments as
they are not needed. Semantic patch:

@@
expression a, b, c;
@@

(
  a = (b == c)
|
  a =
- (
  b
- )
)

Signed-off-by: Janani Ravichandran <janani.rvchndrn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>