staging: ks7010: remove KS_WLAN_MEM_FLAG definition

This commit removes KS_WLAN_MEM_FLAG definition which is
hiding GFP_ATOMIC along the code. It is better to use directly
GFP_ATOMIC in kmalloc's because this it is easier to read.

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