mmc: sh_mobile_sdhi: remove superfluous check in hw_reset

The capability for HW_RESET is only activated if SDR104 is present, so
no need to check for SDR104 in the function itself again.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>