RISC-V: drop error print from riscv_hartid_to_cpuid()

RISC-V: drop error print from riscv_hartid_to_cpuid()

As of commit 2ac874343749 ("RISC-V: split early & late of_node to
hartid mapping") my CI complains about newly added pr_err() messages
during boot, for example:
[    0.000000] Couldn't find cpu id for hartid [0]
[    0.000000] riscv-intc: unable to find hart id for /cpus/cpu@0/interrupt-controller

Before the split, riscv_of_processor_hartid() contained a check for
whether the cpu was "available", before calling riscv_hartid_to_cpuid(),
but after the split riscv_of_processor_hartid() can be called for cpus
that are disabled.

Most callers of riscv_hartid_to_cpuid() already report custom errors
where it falls, making this print superfluous in those case. In other
places, the print adds nothing - see riscv_intc_init() for example.

Fixes: 2ac874343749 ("RISC-V: split early & late of_node to hartid mapping")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230629-paternity-grafted-b901b76d04a0@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>