ath6kl: deinitialise wiphy on error

ath6kl: deinitialise wiphy on error

This fixes the following panic observed on card removal.

BUG: unable to handle kernel paging request at f86e22ac
EIP is at wiphy_update_regulatory+0x252/0x590 [cfg80211]
Call Trace:
 [<f92fb9e5>] set_regdom+0x165/0x600 [cfg80211]
 [<c02057ba>] ? __kmalloc+0x10a/0x190
 [<c0366557>] ? nla_parse+0xb7/0xd0
 [<f9300b92>] ? T.1400+0x12/0x20 [cfg80211]
 [<f9300c84>] nl80211_set_reg+0xe4/0x270 [cfg80211]
 [<f92fe560>] ? nl80211_pre_doit+0x0/0x160 [cfg80211]
 [<c050bdeb>] genl_rcv_msg+0x23b/0x280
 [<c050bbb0>] ? genl_rcv_msg+0x0/0x280
 [<c050ab76>] netlink_rcv_skb+0x86/0xb0
 [<c050bb80>] ? genl_rcv+0x0/0x30
 [<c050bb9c>] genl_rcv+0x1c/0x30

Signed-off-by: Vivek Natarajan <nataraja@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>