ARM: 8922/1: parse_dt_topology() rate is pointer to __be32

The rate pointer in parse_dt_topology is a pointer to a
__be32, not a u32. This fixes the following sparse warning:

arch/arm/kernel/topology.c:128:43: warning: incorrect type in argument 1 (different base types)
arch/arm/kernel/topology.c:128:43:    expected restricted __be32 const [usertype] *p
arch/arm/kernel/topology.c:128:43:    got unsigned int const [usertype] *[assigned] rate

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>