latona:defconfig: enable fixed voltage regulator

Used for powering the WL1271 WIFI Card using vwl1271 fixed voltage regulator
mach:latona: fixup wifi gpios and board reference clock
mach:latona: get rid of config_wlan_mux
We are not required to set the wlan mux in the board since we are already setting it in mux_latona_rev_r08.c
mach:latona:mux: do not request the WLAN_EN gpio
The Fixed Regulator vwl1271 handles the WLAN_EN gpio based on the MMC status. Hence, we dont request WLAN_EN gpio while initializing the board mux.
latona:defconfig: enable building wl12xx sdio driver with mac80211 support