RISC-V: Remove NR_CPUs check during hartid search from DT

In non-smp configuration, hartid can be higher that NR_CPUS.
riscv_of_processor_hartid should not be compared to hartid to NR_CPUS in
that case. Moreover, this function checks all the DT properties of a
hart node. NR_CPUS comparison seems out of place.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>