ima: Finish deprecation of IMA_TRUSTED_KEYRING Kconfig

The removal of IMA_TRUSTED_KEYRING made IMA_LOAD_X509
and IMA_BLACKLIST_KEYRING unavailable because the latter
two depend on the former. Since IMA_TRUSTED_KEYRING was
deprecated in favor of INTEGRITY_TRUSTED_KEYRING use it
as a dependency for the two Kconfigs affected by the
deprecation.

Fixes: 5087fd9e

 ("ima: Remove deprecated IMA_TRUSTED_KEYRING Kconfig")
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>