firmware: Rename FW_OPT_NOFALLBACK to FW_OPT_NOFALLBACK_SYSFS

firmware: Rename FW_OPT_NOFALLBACK to FW_OPT_NOFALLBACK_SYSFS

This is a preparation patch for adding a new platform fallback mechanism,
which will have its own enable/disable FW_OPT_xxx option.

Note this also fixes a typo in one of the re-wordwrapped comments:
enfoce -> enforce.

Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200115163554.101315-4-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>