buildroot: bump to 2024.02.6

2024.02.6, released September 9th, 2024

Important / security related fixes.

 Added a large number of additional runtime tests.

 Infrastructure:
 - Be more robust against text files (for package hashes and
   users) incorrectly missing a terminating newline.

 - Fix various issues with the pkg-kconfig infrastructure and
   per-package-directories builds
   (BR2_PER_PACKAGE_DIRECTORIES).

Updated/fixed packages: aer-inject, am335x-pru-package,
apache, apr, apr-util, attr, boost, btrfs-progs, busybox,
cryptsetup, dropbear, elfutils, fetchmail, ffmpeg, fluidsynth,
freerdp, gcc, gdb, gnutls, gpsd, hiawatha, hostapd, htop,
intel-microcode, iperf3, ksmbd-tools, libcoap, libcurl,
libest, libgtk3, libpwquality, libressl, libupnp, libxml2,
libxslt, lrzsz, mdio-tools, micropython, mjpg-streamer, mpir,
ncftp, nginx, nodejs, open-iscsi, openldap, openvpn, pistache,
procps-ng, python-django, ruby, speex, swaybg, tinyssh,
uclibc, uclibc-ng-test, unbound, uuu, wpewebkit, zfs

 Issues resolved:
- Toolchain (host-gcc-final-14.1.0) build failure with
  y2038/BR2_TIME_BITS_64 enabled
  https://gitlab.com/buildroot.org/buildroot/-/issues/16

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>