sd: sdio: rework frequency and timing selection logic

Reword frequency and timing selection logic for SDIO framework so that
the maximum supported timing mode between the card and host will be
selected, even if the maximum frequency supported by the host is not
equal to the maximum frequency for that mode.

Also, resolve an issue where a host and card combo only supporting HS
mode or worse would still use legacy timing mode, because the CCCR flags
were not being checked when checking if HS bus speed could be used.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>