staging: ks7010: refactor ks_get_wireless_stats function

This commit refactor a bit ks_get_wireless_stats using
ternary operator for return code. It also change a comment
to use preferred style.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>