The ONFI detection routine is too verbose in some cases and not verbose
enough in others. This patch refactors it to print only when there are
significant warnings/errors.

Probing in 16-bit mode:
  It is unnecessary to print until after the READID (address 20h)
  command. READID *has* to work properly in whatever bus width
  configuration we are in, or else no identification mode works. So we
  can silence some useless warnings on systems which come up in 16-bit
  mode and do not even respond with an O-N-F-I string.

Valid parameter page:
  Nobody needs to see this. Do we inform the user every time other
  hardware responds properly? Instead, add an error message if *no*
  uncorrupted parameter pages are found.

ONFI ECC:
  Most drivers don't yet use the reported minimum ECC values, so it
  shouldn't yet be a fatal condition if the extended parameter page is
  incorrect. But we should at least give a warning for the corner cases
  that we don't expect.

ONFI flash detected:
  Nobody needs to see this. This is the expected case, that we detect
  ONFI properly, or else it wasn't ONFI-compliant and is detected by
  some other routine.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Huang Shijie <b32955@freescale.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>