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/bl2_plat_setup.c b/plat/st/stm32mp1/bl2_plat_setup.c
index 5ab20845..c7bc39f 100644
--- a/plat/st/stm32mp1/bl2_plat_setup.c
+++ b/plat/st/stm32mp1/bl2_plat_setup.c
@@ -225,9 +225,7 @@
 		goto skip_console_init;
 	}
 
-	if (stm32mp_clk_enable((unsigned long)dt_uart_info.clock) != 0) {
-		goto skip_console_init;
-	}
+	stm32mp_clk_enable((unsigned long)dt_uart_info.clock);
 
 	stm32mp_reset_assert((uint32_t)dt_uart_info.reset);
 	udelay(2);