powerpc/powernv: Fix overrunning segment tracing array

There're 2 arrays introduced to trace which PE has occupied the
corresponding resource (I/O or MMIO) segment. However, we didn't
allocate enough memory for them and that possiblly leads to PE
descriptor corruption.

The patch fixes that by allocating enough memory for those 2 arrays.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: Ram Pai <linuxram@us.ibm.com>
Reviewed-by: Richard Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>