mwifiex: add packet coalesce support

mwifiex: add packet coalesce support

Coalesce filters are configured in firmware based on settings
received from cfg80211.

Packet type which is required by firmware is determined based on
provided patterns in a rule:

Unicast: if pattern '01' with offset 0 is found
Multicast: if pattern '33:33' or '01:00:5e' with offset 0 is found
Broadcast: if pattern 'ff:ff:ff:ff' with offset 0 is found

Some example coalesce configuration files:

1) Coalesce Rx data packets from 192.168.0.88
mac address of our device is 00:50:43:21:53:7A
Source IP address offset comes out as 52 after following
calculations:
    32 bytes of HW 802.11 header + 8 bytes LLC +
    12 bytes in IPV4 header till source IP address
Destination mac is at offset 6 in HW header.

delay=100
condition=1
patterns=01,6+00:50:43:22,10+53:7A,52+c0:a8:00:58

2) Coalesce all broadcast and multicast packets(Multiple packet
types are not allowed in a single rule. Hence created separate
rules)

delay=400
condition=1
patterns=33:33
delay=400
condition=1
patterns=ff:ff:ff:ff

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>