spi: use new spi_transfer_delay_exec helper where straightforward

For many places in the spi drivers, using the new `spi_transfer_delay`
helper is straightforward.
It's just replacing:
```
  if (t->delay_usecs)
     udelay(t->delay_usecs);
```
with `spi_transfer_delay(t)` which handles both `delay_usecs` and the new
`delay` field.

This change replaces in all places (in the spi drivers)  where this change
is simple.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-10-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-sh-hspi.c

@@ -190,8 +190,7 @@ static int hspi_transfer_one_message(struct spi_controller *ctlr,
 
 		msg->actual_length += t->len;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (cs_change) {
 			ndelay(nsecs);