MMC: Poll card status after rescanning cards

Some broken cards seem to process CMD1 even in stand-by state. The result is
that the card replies with ILLEGAL_COMMAND error for the next command sent
after rescanning. Currently the next command is select card, which would
return the error. But CMD7 does actually succeed and retries of the command
will timeout. The workaround is to poll card status after CMD1 to clear the
pending error.

Signed-off-by: Timo Teras <timo.teras@solidboot.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>