ssl-opt.sh: Enable Non-blocking I/O tests for TLS 1.3

The other "Non-blocking I/O" tests are not relevant
to TLS 1.3 yet: no ticket and session resumption
support.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index f507a32..896e475 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -5657,7 +5657,6 @@
 
 # Tests for non-blocking I/O: exercise a variety of handshake flows
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Non-blocking I/O: basic handshake" \
             "$P_SRV nbio=2 tickets=0 auth_mode=none" \
             "$P_CLI nbio=2 tickets=0" \
@@ -5666,7 +5665,6 @@
             -C "mbedtls_ssl_handshake returned" \
             -c "Read from server: .* bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Non-blocking I/O: client auth" \
             "$P_SRV nbio=2 tickets=0 auth_mode=required" \
             "$P_CLI nbio=2 tickets=0" \