perf/arm-cmn: Add more bits to child node address offset field

CMN-600 uses bits [27:0] for child node address offset while bits [30:28]
are required to be zero.

For CMN-650, the child node address offset field has been increased
to include bits [29:0] while leaving only bit 30 set to zero.

Let's include the missing two bits and assume older implementations
comply with the spec and set bits [29:28] to 0.

Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Fixes: 60d15040

 ("perf/arm-cmn: Support new IP features")
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20220808195455.79277-1-ilkka@os.amperecomputing.com
Signed-off-by: Will Deacon <will@kernel.org>