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_context.c b/plat/st/stm32mp1/stm32mp1_context.c
index c402c20..cf8a91e 100644
--- a/plat/st/stm32mp1/stm32mp1_context.c
+++ b/plat/st/stm32mp1/stm32mp1_context.c
@@ -20,26 +20,16 @@
 
 int stm32_save_boot_interface(uint32_t interface, uint32_t instance)
 {
-	uint32_t tamp_clk_off = 0;
 	uint32_t bkpr_itf_idx = tamp_bkpr(TAMP_BOOT_ITF_BACKUP_REG_ID);
 
-	if (!stm32mp_clk_is_enabled(RTCAPB)) {
-		tamp_clk_off = 1;
-		if (stm32mp_clk_enable(RTCAPB) != 0) {
-			return -EINVAL;
-		}
-	}
+	stm32mp_clk_enable(RTCAPB);
 
 	mmio_clrsetbits_32(bkpr_itf_idx,
 			   TAMP_BOOT_ITF_MASK,
 			   ((interface << 4) | (instance & 0xFU)) <<
 			   TAMP_BOOT_ITF_SHIFT);
 
-	if (tamp_clk_off != 0U) {
-		if (stm32mp_clk_disable(RTCAPB) != 0) {
-			return -EINVAL;
-		}
-	}
+	stm32mp_clk_disable(RTCAPB);
 
 	return 0;
 }