USB: s3c-hsotg: Fix stall condition processing

The following should be done for requests after endpoint stall
condition is cleared:
1) 'in progress' request (if any) should be completed since
   Tx FIFO was flushed;
2) next request from queue (if any) should be started.

This commit does that.

Additionally set/clear stall condition code is fixed.

Signed-off-by: Anton Tikhomirov <av.tikhomirov@samsung.com>
Reviewed-by: Kyoungil <Kim&lt;ki0351.kim@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>