MAINTAINERS: Update files for TMIO/SDHI MMC driver

Update files for tmio/sdhi MMC driver to reflect recent filename
changes.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>