USB: storage: make the "quirks=" module parameter writable

This patch (as1190) makes usb-storage's "quirks=" module parameter
writable, so that users can add entries for their devices at runtime
with no need to reboot or reload usb-storage.

New codes are added for the SANE_SENSE, CAPACITY_HEURISTICS, and
CAPACITY_OK flags.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>