powerpc/8xx: Remove loading of r10 at end of FixupDAR

Since commit 2321f337, r10 is not used anymore
after FixupDAR. There is therefore no need to set it up with the value of DAR.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>