mmc: bus: print bus speed mode of UHS-I card

When UHS-I card is detected also print the bus speed mode in which
UHS-I card will be running.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Acked-by: Aaron Lu <aaron.lu@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>