Align secure boot configs (jsc#SLE-15857 jsc#SLE-13618 bsc#1176918 ltc#186474).
    
    ppc64le:
     +CONFIG_INTEGRITY_PLATFORM_KEYRING=y
     +CONFIG_IMA_APPRAISE_BOOTPARAM=y
     +CONFIG_SYSTEM_BLACKLIST_KEYRING=y
     +CONFIG_SYSTEM_BLACKLIST_HASH_LIST=""
    
    s390x:
     +CONFIG_INTEGRITY_PLATFORM_KEYRING=y
     +CONFIG_LOAD_IPL_KEYS=y
     +CONFIG_SYSTEM_BLACKLIST_KEYRING=y
     +CONFIG_SYSTEM_BLACKLIST_HASH_LIST=""
    
    Signed-off-by: Michal Suchanek <msuchanek@suse.de>