arm32: Potential rollover condition for timer counter

There is potential rollover condition for CNTVCT and
CNTPCT counters. So on any architecture timer counter
read, if the least significant 32 bits are set,
reread counter.

Change-Id: Iacc482ad956d5589d59a2a111576ec0463f5a1bb
Signed-off-by: Tengfei Fan <tengfeif@codeaurora.org>