SPARC/LEON: power down instruction different of different LEONs

SPARC/LEON: power down instruction different of different LEONs

The way a LEON is powered down is implemented differently depending
on CHIP type. The AMBA Plug&Play system ID tells revision of GRLIB
and CHIP.

This is for example needed by the GR-LEON4-ITX board and the UT699.

Previously the power down support for LEON was limited to SMP, now
both SMP and UP systems use the instruction.

Signed-off-by: Daniel Hellstrom <[email protected]>
Acked-by: Sam Ravnborg <[email protected]>
Signed-off-by: David S. Miller <[email protected]>