lantiq: fix ath9k-eeprom for AVM Fritz!Box 7340

@grische noticed that the extracted wifi calibration data (ath9k-eeprom)
is incorrect.
Symptoms included:
- wrong mac address
- radio was detected like dbdc (2.4GHz and 5GHz support at the same time)

This patch fixes this by also reversing the order of bytes and throwing
away the last 4 Bytes.
Unlike caldata.sh the fritz_cal_extract.c doesn't support reversing.
So this patch combines both methods.

Signed-off-by: Felix Baumann <felix.bau@gmx.de>

target/linux/lantiq/xrx200/base-files/etc/hotplug.d/firmware/12-ath9k-eeprom

@@ -23,11 +23,29 @@ case "$FIRMWARE" in
 			avm,fritz7360-v2)
 				caldata_extract "urlader" 0x985 0x1000
 				;;
-			avm,fritz7412|\
-			avm,fritz7430)
+			avm,fritz7412)
 				/usr/bin/fritz_cal_extract -i 1 -s 0x1e000 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader") || \
 				/usr/bin/fritz_cal_extract -i 1 -s 0x1e800 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader")
 				;;
+			avm,fritz7430)
+				reversed=$( \
+				/usr/bin/fritz_cal_extract -i 1 -s 0x1e000 -e 0x207 -l 5120 $(find_mtd_chardev "urlader") || \
+				/usr/bin/fritz_cal_extract -i 1 -s 0x1e800 -e 0x207 -l 5120 $(find_mtd_chardev "urlader") | \
+				hexdump -v -e '/1 "%02x "')
+
+				caldata=""
+				i=0
+				count=$((${#reversed} / 3 - 4))
+				for byte in $reversed; do
+					i=$(($i+1))
+					if [ "$i" -gt "$count" ]; then
+						break
+					fi
+					caldata="\x${byte}${caldata}"
+				done
+
+				printf "%b" "$caldata" > /lib/firmware/$FIRMWARE
+				;;
 			bt,homehub-v5a)
 				caldata_extract_ubi "caldata" 0x1000 0x1000
 				ath9k_patch_mac_crc $(macaddr_add $(mtd_get_mac_binary_ubi caldata 0x110c) 2) 0x10c