main/busybox: increase max log line length from 512 to 2048

The syslog line length was recently increased from 256 to 512 d26ed17b

but as mentioned in this issue #8019 (comment 87629) the recommended length is 2048 and current 512 is not enough for my usage. So I would really appreciate it if we could change it from 512 to 2048. Currently, I have some messages there gets to length 1037 so 2048 would solve it and put us in the safe side 😃

fixes #8019 (closed)