mmc: Fix splitting device initialization

mmc: Fix splitting device initialization

Starting part of device initialization sets the init_in_progress flag
only if the MMC card did not yet come to ready state and needs to continue
polling. If the card is SD or if the MMC card became ready quickly,
the flag is not set and (if using pre-initialization) the starting
phase will be re-executed from mmc_init function.

Set the init_in_progress flag in all non-error cases. Also, move flags
setting statements around so that the flags are not set in error paths.
Also, IN_PROGRESS return status becomes unnecessary, so get rid of it.

Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>