parisc: Fix /proc/cpuinfo output for lscpu

The lscpu command is broken since commit cab56b51 ("parisc: Fix
device names in /proc/iomem") added the PA pathname to all PA
devices, includig the CPUs.

lscpu parses /proc/cpuinfo and now believes it found different CPU
types since every CPU is listed with an unique identifier (PA
pathname).

Fix this problem by simply dropping the PA pathname when listing the
CPUs in /proc/cpuinfo. There is no need to show the pathname in this
procfs file.

Fixes: cab56b51 ("parisc: Fix device names in /proc/iomem")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.9+