riscv: Only check online cpus for emulated accesses

[ Upstream commit 313130c6

 ]

The unaligned access checker only sets valid values for online cpus.
Check for these values on online cpus rather than on present cpus.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Fixes: 71c54b3d

 ("riscv: report misaligned accesses emulation to hwprobe")
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-2-a388770ba0ce@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>