[POWERPC] spufs: Change %llx to 0x%llx.

This patches changes /npc, /decr, /decr_status, /spu_tag_mask,
/event_mask, /event_status, and /srr0 files to provide output according to
the format string "0x%llx" instead of "%llx".

Before this patch some files used "0x%llx" and other used "%llx" which is
inconsistent and potentially confusing. A user might assume "%llx" numbers
were decimal if they happened to not contain any a-f digits. This change
will break any code cannot tolerate a leading 0x in the file contents. The
only known users of these files are the libspe but there might also be
some scripts which access these files. This risk is deemed acceptable for
future consistency.

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>