staging: fwserial: Use normal logging styles

Logging messages without newline termination are subject
to interleaving by other messages.

Avoid this by adding newlines to each message.

Neaten fwtty_<level> logging macros.
Convert driver_err to pr_err.
Add #define pr_fmt to prefix those messages.
Remove now unused driver_err macro.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>