stm32mp1: update clock driver

Remove useless private structure in function prototypes.
Add a reference counter on clocks.
Prepare for future secured/shared/non-secured clocks.

Change-Id: I3dbed81721da5ceff5e10b2c4155b1e340c036ee
Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Nicolas LE BAYON <nicolas.le.bayon@st.com>
diff --git a/plat/st/stm32mp1/stm32mp1_security.c b/plat/st/stm32mp1/stm32mp1_security.c
index baa3916..ebf1587 100644
--- a/plat/st/stm32mp1/stm32mp1_security.c
+++ b/plat/st/stm32mp1/stm32mp1_security.c
@@ -61,14 +61,8 @@
  ******************************************************************************/
 static void early_init_tzc400(void)
 {
-	if (stm32mp_clk_enable(TZC1) != 0) {
-		ERROR("Cannot enable TZC1 clock\n");
-		panic();
-	}
-	if (stm32mp_clk_enable(TZC2) != 0) {
-		ERROR("Cannot enable TZC2 clock\n");
-		panic();
-	}
+	stm32mp_clk_enable(TZC1);
+	stm32mp_clk_enable(TZC2);
 
 	tzc400_init(STM32MP1_TZC_BASE);