configs/atmel_sama5d27_som1: add rng-tools package

More entropy is required at boot time for the ssh
daemon to start.

So, enable rngd which feeds the entropy to the kernel
entropy tool.

Signed-off-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/atmel_sama5d27_som1_ek_mmc_dev_defconfig

@@ -41,6 +41,7 @@ BR2_PACKAGE_WILC1000_FIRMWARE=y
 BR2_PACKAGE_DEVMEM2=y
 BR2_PACKAGE_EVTEST=y
 BR2_PACKAGE_I2C_TOOLS=y
+BR2_PACKAGE_RNG_TOOLS=y
 BR2_PACKAGE_SETSERIAL=y
 BR2_PACKAGE_SPI_TOOLS=y
 BR2_PACKAGE_USBUTILS=y