powerpc/8xx: Remove last traces of 8XX_MINIMAL_FPEMU

The Kconfig symbol 8XX_MINIMAL_FPEMU was removed in commit 968219fa


("powerpc/8xx: Remove 8xx specific "minimal FPU emulation""). But that
commit didn't remove all code depending on that symbol. Do so now.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>