checkpatch: Prefer seq_puts to seq_printf

Add a check for seq_printf use with a constant format without additional
arguments.  Suggest seq_puts instead.

Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>