Usage messages should use the same EBNF as the User's Guide;
no angle brackets.  Be more complete too ... some params were
missing.  Improve and correct various helptexts.

Make user's guide refer to the NAND "driver" name, not the
controller name; that's a bit more precise.

Don't use "&function"; its name is its address.  Line up struct
initializers properly.  Remove some blank lines.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>