toolchain: unbreak glibc on MIPS

Binutils recently updated the ABI version to 5, which broke glibc, as it
refuses to load anything > 3. Upstream reverted the ABI version update,
so backport the commit.

Fixes the following error on boot:

/bin/sh: error while loading shared libraries: /lib/libcrypt.so.1: ELF file ABI version invalid
[    0.920077] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00
[    0.920077]
[    0.929450] Rebooting in 1 seconds..

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>