spi: use sysfs_emit() for printing statistics and add trailing newline

Use dedicated function sysfs_emit() that does some extra checking,
e.g. to ensure that no more than PAGESIZE bytes are written.
In addition add a trailing newline to the output, that makes it
better readable from the console.

Signed-off-by: Heiner Kallweit <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi.c

···
 	unsigned long flags;						\
 	ssize_t len;							\
 	spin_lock_irqsave(&stat->lock, flags);				\
-	len = sprintf(buf, format_string, stat->field);			\
+	len = sysfs_emit(buf, format_string "\n", stat->field);		\
 	spin_unlock_irqrestore(&stat->lock, flags);			\
 	return len;							\
 }									\