ath5k: add PCI id

ath5k: add PCI id

This device works fine of ath5k.

Details bellow
05:00.0 0200: 168c:ff1b (rev 01)
05:00.0 Ethernet controller: Atheros Communications Inc. Device ff1b (rev 01)
	Flags: bus master, fast devsel, latency 0, IRQ 19
	Memory at febf0000 (64-bit, non-prefetchable) [size=64K]
	Capabilities: <access denied>
	Kernel driver in use: ath5k

ath5k 0000:05:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19
ath5k 0000:05:00.0: setting latency timer to 64
ath5k 0000:05:00.0: registered as 'phy0'
ath: EEPROM regdomain: 0x67
ath: EEPROM indicates we should expect a direct regpair map
ath: Country alpha2 being used: 00
ath: Regpair used: 0x67
ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
ath5k phy0: Atheros AR2425 chip found (MAC: 0xe2, PHY: 0x70)

Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: John W. Linville <linville@tuxdriver.com>