ath: Fix uninitialized variable warnings

Fixes 'make -j24 CONFIG_DEBUG_SECTION_MISMATCH=y' warning:

drivers/net/wireless/ath/ath9k/eeprom_4k.c: In function ‘ath9k_hw_get_4k_gain_boundaries_pdadcs.clone.1’:
drivers/net/wireless/ath/ath9k/eeprom_4k.c:311: error: ‘minPwrT4’ may be used uninitialized in this function
drivers/net/wireless/ath/ath9k/eeprom_9287.c: In function ‘ath9k_hw_get_AR9287_gain_boundaries_pdadcs’:
drivers/net/wireless/ath/ath9k/eeprom_9287.c:302: error: ‘minPwrT4’ may be used uninitialized in this function
drivers/net/wireless/ath/ath9k/eeprom_def.c: In function ‘ath9k_hw_get_def_gain_boundaries_pdadcs.clone.0’:
drivers/net/wireless/ath/ath9k/eeprom_def.c:679: error: ‘minPwrT4’ may be used uninitialized in this function

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/eeprom_4k.c b/drivers/net/wireless/ath/ath9k/eeprom_4k.c
index 41a77d1..e25a2ab 100644
--- a/drivers/net/wireless/ath/ath9k/eeprom_4k.c
+++ b/drivers/net/wireless/ath/ath9k/eeprom_4k.c
@@ -249,6 +249,7 @@
 	struct chan_centers centers;
 #define PD_GAIN_BOUNDARY_DEFAULT 58;
 
+	memset(&minPwrT4, 0, AR9287_NUM_PD_GAINS);
 	ath9k_hw_get_channel_centers(ah, chan, &centers);
 
 	for (numPiers = 0; numPiers < availPiers; numPiers++) {