apparmor: correct config reference to intended one

Commit 5bfcbd22 ("apparmor: Enable tuning of policy paranoid load for
embedded systems") introduces the config SECURITY_APPARMOR_PARANOID_LOAD,
but then refers in the code to SECURITY_PARANOID_LOAD; note the missing
APPARMOR in the middle.

Correct this to the introduced and intended config option.

Fixes: 5bfcbd22

 ("apparmor: Enable tuning of policy paranoid load for embedded systems")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>