deb: s390x no WolfSSL workaround as upstream fixed in 4.6.0

https://github.com/wolfSSL/wolfssl/issues/2828 lists 4.6.0 a
as the fixed version as we currently have 4.8.0.

Since the time of the above issue, Debian has allowed OpenSSL
linking.

debian/rules

@@ -52,14 +52,6 @@ ifneq ($(DEB_BUILD_ARCH),$(DEB_HOST_ARCH))
     endif
 endif
 
-# Add extra flag to avoid WolfSSL code crashing the entire mariadbd on s390x. This
-# can be removed once upstream has made the code s390x compatible, see
-# https://jira.mariadb.org/browse/MDEV-21705 and
-# https://github.com/wolfSSL/wolfssl/issues/2828
-ifeq ($(DEB_HOST_ARCH),s390x)
-    CFLAGS += -DWC_NO_CACHE_RESISTANT
-endif
-
 # Add support for verbose builds
 MAKEFLAGS += VERBOSE=1