RISC-V: defconfigs: Sort CONFIG_PTP_1588_CLOCK

This should have no functional change, it just sorts
CONFIG_PTP_1588_CLOCK the same way savedefconfig does.  This only
touches the rv64 defconfig because rv32_defconfig was already sorted
correctly.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>