s3cmci: Fix hangup in do_pio_write()

This commit fixes the regression what was added by commit
088a78af978d0c8e339071a9b2bca1f4cb368f30 "s3cmci: Support transfers
which are not multiple of 32 bits."

fifo_free() now returns amount of available space in FIFO buffer in
bytes.  But do_pio_write() writes to FIFO 32-bit words.  Condition for
return from cycle is (fifo_free() == 0), but when fifo has 1..3 bytes
of free space then this condition will never be true and system hangs.

This patch changes condition in the while() to (fifo_free() > 3).

Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/host/s3cmci.c

@@ -329,7 +329,7 @@ static void do_pio_write(struct s3cmci_host *host)
 
 	to_ptr = host->base + host->sdidata;
 
-	while ((fifo = fifo_free(host))) {
+	while ((fifo = fifo_free(host)) > 3) {
 		if (!host->pio_bytes) {
 			res = get_data_buffer(host, &host->pio_bytes,
 							&host->pio_ptr);