[nrf fromtree] samples: net: wifi: enable time checking for mbedtls cert files

enable time checking for mbedtls certificate files, return failed
if certificate files expired.

Signed-off-by: Rex Chen <[email protected]>
(cherry picked from commit 6551e40)

Author: Rex-Chen-NXP

samples/net/wifi/boards/rd_rw612_bga.conf

@@ -91,6 +91,7 @@ CONFIG_MBEDTLS=y
 CONFIG_MBEDTLS_BUILTIN=y
 CONFIG_MBEDTLS_USER_CONFIG_ENABLE=y
 CONFIG_MBEDTLS_USER_CONFIG_FILE="wpa_supp_els_pkc_mbedtls_config.h"
+CONFIG_MBEDTLS_HAVE_TIME_DATE=y
 
 # Include els_pkc in build
 CONFIG_ENTROPY_GENERATOR=y