ath10k: minimally handle new channel width enumeration values

  CC      drivers/net/wireless/ath/ath10k/mac.o
drivers/net/wireless/ath/ath10k/mac.c: In function ‘chan_to_phymode’:
drivers/net/wireless/ath/ath10k/mac.c:229:3: warning: enumeration value ‘NL80211_CHAN_WIDTH_5’ not handled in switch [-Wswitch]
drivers/net/wireless/ath/ath10k/mac.c:229:3: warning: enumeration value ‘NL80211_CHAN_WIDTH_10’ not handled in switch [-Wswitch]
drivers/net/wireless/ath/ath10k/mac.c:247:3: warning: enumeration value ‘NL80211_CHAN_WIDTH_5’ not handled in switch [-Wswitch]
drivers/net/wireless/ath/ath10k/mac.c:247:3: warning: enumeration value ‘NL80211_CHAN_WIDTH_10’ not handled in switch [-Wswitch]

Signed-off-by: John W. Linville <linville@tuxdriver.com>