ipl: Enable FPU and remove workarounds

It turns out, that the FPU isn't initialized by firmware, which is
why the floating point instructions in libgcc's __udivdi3, __umoddi3
and __muldi3 routines simply hangs the machine.

This patch enables the FPU at bootup and thus we can drop the
current work-arounds.

Signed-off-by: Helge Deller <deller@gmx.de>