mmc: dw_mmc: enable controller interrupt before calling mmc_start_host

As mmc_start_host is getting called before enabling the dw_mmc controller
interrupt, there is a problem of missing the SDMMC_INT_CMD_DONE for the
very first command sent by the sdio_reset.

This problem occurs only when we disable MMC debugging i.e, MMC_DEBUG=n.
This patch enables the dw_mmc controller interrupt before mmc_start_host.

Signed-off-by: Yuvaraj CD <yuvaraj.cd@samsung.com>
Reviewed-by: Girish K S <girish.shivananjappa@linaro.org>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>