mmc: omap_hsmmc: refactor duplicated code

There are a few places with the same functionality. This patch creates
two functions omap_hsmmc_set_bus_width() and omap_hsmmc_set_bus_mode()
to do the job.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>