bcm53xx: calculate TRX CRC32 using whole kernel partition

This provides better protection of flash data.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

target/linux/bcm53xx/base-files/etc/uci-defaults/09_fix_crc

@@ -1,3 +1,8 @@
 #!/bin/sh
 
-mtd fixtrx firmware || mtd fixseama firmware
+kernel_size=$(sed -n 's/mtd[0-9]*: \([0-9a-f]*\).*"\(kerel\|liux\)".*/\1/p' /proc/mtd)
+[ -n "$kernel_size" ] && kernel_size=$((0x$kernel_size))
+
+mtd ${kernel_size:+-c $kernel_size} fixtrx firmware && exit 0
+mtd fixseama firmware && exit 0
+exit 1