check_signature is a bool option and doesn't take any arguments. The
presence of the 1 falsely suggests setting it to 0 disables the check,
while the option actually needs to be removed or commented out to be
disabled. So remove the argument to make it more clear.
Fixes: beca028bd6 ("build: add integration for managing opkg package feed keys")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>