Changeset f419349 in rtems for bsps

bsps/powerpc: Adjust ppcboot.lds

The GNU ld had a couple of changes which resulted in a broken bootloader
image generation. Recent linker versions tie assignments to their
nearest output section statement. Place all absolute symbols which are
used with @sectoff relocations into a special section.

See also:

"Binutils 2.28 on PowerPC: dangerous relocation: generic linker can't
handle R_PPC_SECTOFF_HA"

​https://www.sourceware.org/ml/binutils/2019-05/msg00183.html

Update #3727