ARM: DT/kernel: define ARM specific arch_match_cpu_phys_id

OF/DT core library now provides architecture specific hook to match the
logical cpu index with the corresponding physical identifier. Most of the
cpu DT node parsing and initialisation is contained in devtree.c. So it's
better to define ARM specific arch_match_cpu_phys_id there.

This mainly helps to avoid replication of the code doing CPU node parsing
and physical(MPIDR) to logical mapping.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>