mmc: split mmc_startup()

No functionnal change here. The function is really big and can be split.
The part related to bus configuration are put in 2 separate functions: one
for MMC and one for SD.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed