bootparam.7: Remove crufty floppy disk driver options

bootparam.7: Remove crufty floppy disk driver options

[Part of a general change to remove cruft from this page.]
Much of the detail on device-driver specifics in this page dates
from the 20th century. (The last major update to this page was in
man-pages-1.14!) It's hugely out of date now (many of these
devices disappeared from the kernel years ago.) Arguably, this
kind of detail should never have been placed in a man page to
begin with, since devices come and go. Remove such text, and
where appropriate and possible add pointers to files in the
kernel Documentation/ directory.

In the specific case of floppy drives: the drivers still
exist, but it's been a while since most of saw these devices
in the wild. So, just refer the reader to the kernel source
file for details. (The detail in this man page was after all
originally drawn from that file.)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>