MIPS: OCTEON: Extend number of supported CPUs past 32

MIPS: OCTEON: Extend number of supported CPUs past 32

To support more than 48 CPUs, the bootinfo structure grows a new
coremask structure.  Add the definition of the structure and add it to
struct cvmx_bootinfo.  In prom_init(), copy the new coremask data into
the sysinfo structure, and use it in smp_setup().

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12319/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>