staging: rtl8192u: r8192U_core: fix comments lines over 80 characters

Move, replace and reorganize comments to stay under 80 characters
per line, as to follow the kernel code style. Some unuseful comments
have been removed.

Signed-off-by: Raphaël Beamonte <raphael.beamonte@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>