staging: pi433: Use preferred commenting style

For multi-line comments, the preferred commenting style from the
coding style Documentation was applied to the comments, meaning
almost blank lines at the beginning and end of the comment.
One changed comment includes a line over 80 characters, causing
checkpatch.pl to complain, however breaking this line would not
make much sense, so it is kept like it is.

Signed-off-by: Sophie Matter <sophie.matter@web.de>
Signed-off-by: Rico Schrage <rico.schrage@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>