staging: wilc1000: Modify tcp_process to return void rather than int

tcp_process() returns int, which is not used anywhere. So, change
function header to return void intead of int and remove all uses of
the local variable ret, which is used as a return variable in the
function.

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