board: amlogic: select PWRSEQ for all amlogic platform

commit a10388dc ("mmc: meson-gx: add support for mmc-pwrseq-emmc")
introduce CONFIG_PWRSEQ for power sequence for eMMC module on
amlogic platform, so enable this to all amlogic boards.

Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>