MAINTAINERS: remove David Safford as maintainer for encrypted+trusted keys

Emails to David's listed email address bounce, and in the commit log
there's no activity from him within the last 5 years.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Safford <safford@us.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

MAINTAINERS

@@ -7625,7 +7625,6 @@ F:	kernel/kexec*
 
 KEYS-ENCRYPTED
 M:	Mimi Zohar <zohar@linux.vnet.ibm.com>
-M:	David Safford <safford@us.ibm.com>
 L:	linux-security-module@vger.kernel.org
 L:	keyrings@vger.kernel.org
 S:	Supported
@@ -7634,7 +7633,6 @@ F:	include/keys/encrypted-type.h
 F:	security/keys/encrypted-keys/
 
 KEYS-TRUSTED
-M:	David Safford <safford@us.ibm.com>
 M:	Mimi Zohar <zohar@linux.vnet.ibm.com>
 L:	linux-security-module@vger.kernel.org
 L:	keyrings@vger.kernel.org