boards: arm: enabling hsi48 for SDMMC peripheral on stm32 platforms

The different boards with stm32 which have node enabled in their DTS
also requires the HSI48 clock to be enabled.

Signed-off-by: Francois Ramu <francois.ramu@st.com>
diff --git a/boards/arm/stm32h7b3i_dk/stm32h7b3i_dk.dts b/boards/arm/stm32h7b3i_dk/stm32h7b3i_dk.dts
index d08585f..6fb8cd6 100644
--- a/boards/arm/stm32h7b3i_dk/stm32h7b3i_dk.dts
+++ b/boards/arm/stm32h7b3i_dk/stm32h7b3i_dk.dts
@@ -66,6 +66,10 @@
 	};
 };
 
+&clk_hsi48 {
+	status = "okay";
+};
+
 &clk_hse {
 	clock-frequency = <DT_FREQ_M(24)>;
 	status = "okay";
diff --git a/boards/arm/stm32l496g_disco/stm32l496g_disco.dts b/boards/arm/stm32l496g_disco/stm32l496g_disco.dts
index 32fc90b..3545295 100644
--- a/boards/arm/stm32l496g_disco/stm32l496g_disco.dts
+++ b/boards/arm/stm32l496g_disco/stm32l496g_disco.dts
@@ -67,6 +67,10 @@
 	status = "okay";
 };
 
+&clk_hsi48 {
+	status = "okay";
+};
+
 &clk_hsi {
 	status = "okay";
 };