tifm_sd: alter order of the states in the command handler

Previously, stop command was issued right after BRS (block received/sent)
event. Stop command completion event could interfere with the card busy
event, causing miscount of the written blocks.
This patch ensures that stop command issued as last action for a
particular command, after DMA sompletion event and written block
count verification.

Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>