plat-sam: enable nvmem support

Enable nvmem support to allow reading hardware unique key from the fuses.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Thomas Perrot <thomas.perrot@bootlin.com>
Acked-by: Etienne Carriere <etienne.carriere@foss.st.com>

core/arch/arm/plat-sam/conf.mk

@@ -108,3 +108,6 @@ $(call force,CFG_SCMI_MSG_CLOCK,y)
 $(call force,CFG_SCMI_MSG_USE_CLK,y)
 $(call force,CFG_SCMI_MSG_SMT_FASTCALL_ENTRY,y)
 endif
+
+CFG_DRIVERS_NVMEM ?= y
+CFG_ATMEL_SFC ?= y