powerpc: Remove Cell-specific relocation-on interrupt vector code

The Cell processor doesn't support relocation-on interrupts, so we
don't need relocation-on versions of the interrupt vectors that are
purely Cell-specific.  This removes them.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>