ath6kl: Configure WOW patterns while going to wow_suspend

First preference is given to the user configured WOW patterns.
If the user doesn't configure any patterns (for ex, via iw command),
the default patterns will be configured based on the current mode
(vif->nw_type) while going to WOW suspend.

Summary of changes:

  * ath6kl_wow_ap() is added to configure the below default
    patterns when the system enters into WOW suspend in AP mode.
      + Unicast IP, EAPOL-like and ARP packet pattern
      + ARP packet pattern
      + mDNS/SSDP/LLMNR pattern
      + DHCP broadcast pattern

 * ath6kl_wow_sta() is added to configure the below default
   patterns when the system enters into WOW suspend in STA mode.
      + Unicast packet pattern
      + mDNS/SSDP/LLMNR pattern

  * Move the user provided WOW patterns configuration code
    from ath6kl_wow_suspend() to a separate function called
    ath6kl_wow_usr().

  * Two argument variable's ('filter' and 'mask) data type in
    ath6kl_wmi_add_wow_pattern_cmd() are changed from 'u8 *' to
    'const u8 *'. This is needed to make all pattern and mask
    arrays to be 'static const u8' in the caller function.

  * New conditional check is added to make sure user
    configured pattern count is within the limit (WOW_MAX_FILTERS_PER_LIST).

Signed-off-by: Raja Mani <rmani@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>