mwifiex: add WOWLAN support

Currently 'magic-packet' and 'patterns' options in 'iw wowlan'
command are supported.

Appropriate packet filters for wowlan are configured in firmware
based on provided patterns and/or magic-packet option.

For examples,

wake-on ARP request for 192.168.0.100:
iw phy0 wowlan enable patterns ff:ff:ff:ff:ff:ff 20+08:06
  46+c0:a8:00:64

wake-on RX packets sent from IP address 192.168.0.88:
iw phy0 wowlan enable patterns 34+c0:a8:00:58

wake-on RX packets with TCP destination port 80
iw phy0 wowlan enable patterns 44+50

wake-on MagicPacket:
iw phy0 wowlan enable magic-packet

wake-on MagicPacket or patterns:
iw phy0 wowlan enable magic-packet patterns 12+00:11:22:33:44:55
  18+00:50:43:21

wake-on IPv4 multicast packets:
iw phy0 wowlan enable patterns 01:00:5e

wake-on IPv6 multicast packets:
iw phy0 wowlan enable patterns 33:33

disable all wowlan options
iw phy0 wowlan disable

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>