Rename the source file SDHI. A follow-up patch will make it a library
file used by a different top-level module file.

The name "renesas" is chosen as the SDHI driver is applicable to a wider
range of SoCs than SH-Mobile it seems to be a more appropriate name.
However, the SDHI driver source itself, is left as sh_mobile_sdhi to
avoid unnecessary churn.

the name "core" was chosen to reflect the desired role of this file,
to provide core functionality to the sdhi driver. A follow-up patch will
move the file into that role.

Internal symbols have also been renamed to reflect the filename change.

The .name member of struct platform_driver and parameter to
MODULE_ALIAS() have not been changed in order to avoid the complication
of potentially breaking SH SoCs which still use platform drivers.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>