Some old MMC devices fail with the 4/8 bits the driver tries to use
exclusively.  This patch adds a test for the given bus setup and falls
back to the lower bit mode (until 1-bit mode) when the test fails.

[Major rework and refactoring by tiwai]
[Quirk addition and many fixes by prakity]
Signed-off-by: NAries Lee <arieslee@jmicron.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NPhilip Rakity <prakity@marvell.com>
Tested-by: NPhilip Rakity <prakity@marvell.com>
Signed-off-by: NChris Ball <cjb@laptop.org>