[POWERPC] spufs: Add /lslr, /dma_info and /proxydma files

The /lslr file gives read access to the SPU_LSLR register in hex; 0x3fff
for example The /dma_info file provides read access to the SPU Command
Queue in a binary format. The /proxydma_info files provides read access
access to the Proxy Command Queue in a binary format. The spu_info.h
file provides data structures for interpreting the binary format of
/dma_info and /proxydma_info.

Signed-off-by: Dwayne Grant McConnell <decimal@us.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>