parisc: correctly display number of active CPUs

In case we fail to power up other CPUs in a SMP system, the kernel
currently shows a wrong number of online CPUs. This change makes the
output more verbose on how many of the CPUs are online. Example:

CPU(s): 1 out of 2 PA8800 (Mako) at 900.000000 MHz online.

Signed-off-by: Helge Deller <deller@gmx.de>