staging: rtl8712: Remove return variable of different type

The local return variable ret may be replaced directly by its value,
especially since its type (uint) is not the same as the function's
return type (int).
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>