mmc: tmio: fix never-detected card insertion bug

The TMIO mmc cannot detect the card insertion in native_hotplug mode
if the driver is probed without a card inserted.

The reason is obvious; all IRQs are disabled by tmio_mmc_host_probe(),
as follows:

  tmio_mmc_disable_mmc_irqs(_host, TMIO_MASK_ALL);

The card event IRQs are first enabled by tmio_mmc_start_command() as
follows:

  if (!host->native_hotplug)
          irq_mask &= ~(TMIO_STAT_CARD_REMOVE | TMIO_STAT_CARD_INSERT);
  tmio_mmc_enable_mmc_irqs(host, irq_mask);

If the driver is probed without a card, tmio_mmc_start_command() is
never called in the first place.  So, the card is never detected.

The card event IRQs must be enabled in probe/resume functions.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>