staging: rtl8188eu: Removed unnecessary parentheses

Removed unnecessary parentheses and this resolve the check patch issue.

Structure dereference operator have higher precedence then Address of
operator So there is no need of parentheses.

This change is purely coding style in nature and should have not effect
on runtime code execution.

Signed-off-by: Bhaskar Singh <bhaskar.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>