feat(stm32mp1): register fixed regulator

Register fixed regulator in BL2.

Change-Id: I24292f549b2cd24fb717fbb68eb95af7aa68e3b9
Signed-off-by: Pascal Paillet <p.paillet@st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
diff --git a/plat/st/stm32mp1/platform.mk b/plat/st/stm32mp1/platform.mk
index d6fe131..fec4cb1 100644
--- a/plat/st/stm32mp1/platform.mk
+++ b/plat/st/stm32mp1/platform.mk
@@ -201,6 +201,7 @@
 				drivers/st/pmic/stm32mp_pmic.c				\
 				drivers/st/pmic/stpmic1.c				\
 				drivers/st/regulator/regulator_core.c			\
+				drivers/st/regulator/regulator_fixed.c			\
 				drivers/st/reset/stm32mp1_reset.c			\
 				plat/st/common/stm32mp_dt.c				\
 				plat/st/stm32mp1/stm32mp1_dbgmcu.c			\