hw/pxa2xx.c: Fix handling of R/WC bits in PMCR Fix a bug in handling the write-one-to-clear bits in the PMCR which meant that we would always clear the bit even if the value written was a zero. Spotted by Coverity (see bug 887883). Signed-off-by: Peter Maydell <[email protected]> Signed-off-by: Anthony Liguori <[email protected]>