certs: remove misleading comments about GCC PR

This dependency is necessary irrespective of the mentioned GCC PR
because the embedded certificates are build artifacts and must be
generated by extract_certs before *.S files are compiled.

The comment sounds like we are hoping to remove these dependencies
someday. No, we cannot remove them.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

certs/Makefile

@@ -19,7 +19,6 @@ ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
 
 $(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
 
-# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
 $(obj)/system_certificates.o: $(obj)/x509_certificate_list
 
 $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
@@ -80,7 +79,6 @@ ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword
 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
 endif
 
-# GCC PR#66871 again.
 $(obj)/system_certificates.o: $(obj)/signing_key.x509
 
 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE