staging: ks7010: avoid some if-else code in get_current_ap function

This commits avoid some if-else code extracting common code before
its use and making use of a new variable 'size' which is assigned
using a ternary operator. This improves readability.

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