ARM: s3c: Kconfig.s3c64xx: Fix indentation

The convention for indentation seems to be a single tab. Help text is
further indented by an additional two whitespaces. Fix the lines that
violate these rules.
Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Link: https://lore.kernel.org/r/20220609082154.115301-4-juerg.haefliger@canonical.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>