hw/pxa2xx: Fix transposed crn/crm values for pxa2xx cp14 perf regs

When the pxa2xx performance counter related cp14 registers were converted
from a switch-statement implementation to the new table driven cpregs
format in commit dc2a9045, the crn and crm values for all these
registers were accidentally transposed. Fix this mistake, which was
causing OpenBSD for Zaurus to fail to boot.

Reported-by: Jonathan Gray <jsg@jsg.id.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>