floppy: make sure to reset all FDCs upon resume()

In floppy_resume() we don't properly reinitialize all FDCs, instead
we reinitialize the current FDC once per available FDC because value
-1 is passed to user_reset_fdc(). Let's simply save the current drive
and properly reinitialize each FDC.

Link: https://lore.kernel.org/r/20200410101904.14652-1-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>