mmc: tmio: use devm_ioremap_resource() instead of devm_ioremap()

The TMIO core misses to call request_mem_region().
devm_ioremap_resource() takes care of it and makes the code cleaner.

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