feat(st-drivers): introduce fixed regulator driver

Fixed regulator is mainly used when no pmic is available

Change-Id: Ib6a998684bcb055ba95a093bee563372d9051474
Signed-off-by: Pascal Paillet <p.paillet@st.com>
diff --git a/include/drivers/st/regulator_fixed.h b/include/drivers/st/regulator_fixed.h
new file mode 100644
index 0000000..b981262
--- /dev/null
+++ b/include/drivers/st/regulator_fixed.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2021, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef REGULATOR_FIXED_H
+#define REGULATOR_FIXED_H
+
+int fixed_regulator_register(void);
+
+#endif /* REGULATOR_FIXED_H */