certs: make system keyring depend on x509 parser

This code requires x509_load_certificate_list() to be built-in.

Fixes: 60050ff ("certs: Move load_certificate_list() to be with the asymmetric keys code")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/202206221515.DqpUuvbQ-lkp@intel.com/
Link: https://lore.kernel.org/all/20220712104554.408dbf42@gandalf.local.home/
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: kilobyte

certs/Kconfig

@@ -43,6 +43,7 @@ config SYSTEM_TRUSTED_KEYRING
 	bool "Provide system-wide ring of trusted keys"
 	depends on KEYS
 	depends on ASYMMETRIC_KEY_TYPE
+	depends on X509_CERTIFICATE_PARSER
 	help
 	  Provide a system keyring to which trusted keys can be added.  Keys in
 	  the keyring are considered to be trusted.  Keys may be added at will