package/rpi-firmware: bump version to 2ef3800

package/rpi-firmware: bump version to 2ef3800

- bump version to 2ef3800 (past [1] which fixes the boot starvation
  introduced by [2] as reported by Vincent Fazio <[email protected]>
  see [3] and [4])

[1] https://github.com/raspberrypi/firmware/commit/b5257da58c0e652633592c6fce09a7f3b100a2eb
[2] https://github.com/raspberrypi/firmware/commit/25e2b597ebfb2495eab4816a276758dcc6ea21f1
[3] http://lists.busybox.net/pipermail/buildroot/2021-September/623659.html
[4] http://lists.busybox.net/pipermail/buildroot/2021-September/624550.html

Signed-off-by: Peter Seiderer <[email protected]>
Signed-off-by: Thomas Petazzoni <[email protected]>