Usage syntax messages have the same EBNF as the User's Guide;
there should be no angle brackets in either place.

Uupdate some helptext to be more accurate.

Fix the User's Guide in a few places to be more consistent (mostly
to use brackets not parentheses) and to recognize that parameter may
be entirely optional (in which case the command just displays output,
and changes nothing).  Also reference NXP, not Philips, for LPC chips.

Don't use "&function"; functions are like arrays, their address
is their name.

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