busybox: set default log buffer size to 64 at compile time

busybox: set default log buffer size to 64 at compile time

This provides a more reasonable log buffer size to avoid losing earlier
events, and 64K is not a problem for modern systems. When the buffer is
used on sysvinit-based systems, which it isn't by default, 64K is already
the runtime default size unless /etc/syslog-startup.conf is modified or
deleted, so this only really affects systems using systemd. This
completely removes the need for the busybox bbappend in meta-oe.

(From OE-Core rev: 6d6a3f805b0fad6f904afb52dc12bfb543e3eec5)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>