mmc: sdhci: use IS_ENABLE(CONFIG_LEDS_CLASS) to enable LED struct members

defined(CONFIG_LEDS_CLASS) || defined(CONFIG_LEDS_CLASS_MODULE)

is equivalent to:

IS_ENABLED(CONFIG_LEDS_CLASS)

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>