iwlwifi: mvm: disable scheduled scan to prevent firmware crash

There are firmwares which don't support scheduled scan.
Disable it for now.
Linus's system encoutered this issue.
Thanks to David Spinadel for his help.

Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>