Documentation: ABI: sysfs-bus-counter: Fix indentation

Fix the indentation of the KernelVersion, Contact, and Description in
external_input_phase_clock_select_available block by replacing
spaces with tabs similar to other blocks.

Reported-by: Pavel Machek <pavel@denx.de>
Closes: https://lore.kernel.org/r/ZH8D3lCobUJP2T4K@duo.ucw.cz/
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230721151243.282435-1-biju.das.jz@bp.renesas.com/
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>