ARM: dts: stm32: change nvmem node name on stm32mp1

Change non volatile node name from nvmem to efuse to be compliant
with yaml schema.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp151.dtsi

@@ -1485,7 +1485,7 @@ rtc: rtc@5c004000 {
 			status = "disabled";
 		};
 
-		bsec: nvmem@5c005000 {
+		bsec: efuse@5c005000 {
 			compatible = "st,stm32mp15-bsec";
 			reg = <0x5c005000 0x400>;
 			#address-cells = <1>;