boards: Add RNG default selection, supplicant and tcp config settings

This change brings in certain default configurations that are needed
for selection of random number generator, and to set tcp
configuration CONFIG_NET_TCP_ISN_RFC6528=n for nRF7002dk board.

Signed-off-by: Vivekananda Uppunda <[email protected]>

Author: VivekUppunda

boards/nordic/nrf7002dk/nrf7002dk_nrf5340_cpuapp_defconfig

@@ -18,3 +18,10 @@ CONFIG_SERIAL=y
 # Enable console
 CONFIG_CONSOLE=y
 CONFIG_UART_CONSOLE=y
+
+# Enable RNG
+CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG=y
+CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG=y
+
+# ISN needs CS-Rand which isn't supported upstream for nRF boards
+CONFIG_NET_TCP_ISN_RFC6528=n