configs: stm32mp15: Enable random number generator(rng) device

Enable support for the rng device on the stm32mp15 configs.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/configs/stm32mp15_basic_defconfig b/configs/stm32mp15_basic_defconfig
index 713a7e6..c85369c 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -143,3 +143,5 @@
 CONFIG_VIDEO_STM32_MAX_XRES=1280
 CONFIG_VIDEO_STM32_MAX_YRES=800
 CONFIG_FDT_FIXUP_PARTITIONS=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_STM32MP1=y